2001

Wednesday 9 January 2002

Summary

Extremely low annual rainfall in the eastern South Island and parts of the lower North Island, despite wet end-of-year conditions
Severe summer–autumn drought, mid-winter freeze
Many other extreme events

For the first year of the new millennium, New Zealand’s climate records continued to tumble. Senior climate scientist Dr Jim Salinger said the National Institute of Water and Atmospheric Research (NIWA) analysis of the year’s weather showed new local records being set in some months, both for average and extreme temperature. “2001 was one of the driest years on record in many eastern South Island areas, as well as parts of Wellington, despite wet October-December conditions,” Dr Salinger said.

“The North Island bore the brunt of eleven rainfall/flooding extremes. Tornadoes also featured in 2001, with at least eight reported, along with an unusual number of wind events, many of them causing property damage. The year featured many new climate records and extremes, with five unusually warm months, and two much colder than average months. There were six cold snaps last winter, four with snow and two with extreme frosts. There were at least two widespread and damaging hailstorms, with hailstones the size of golf balls.”

Higher than average pressures occurred from the South Tasman Sea across the lower South Island and east past the Chatham Islands. Pressures were below average in the north Tasman Sea and to the north. This pattern resulted in more frequent easterlies and north-easterlies over the north of the North Island and more settled conditions elsewhere. Analyses of month-by-month records for the year compared with recorded statistics for previous years show:

  • The year’s national average temperature was 12.8°C (0.3°C above the 1961–1990 normal).
  • The highest annual mean temperature recorded for the year was 16.9°C recorded at CapeReinga.
  • The highest recorded extreme temperature for the year was 35.3°C recorded at Timaru Airport on 4 February, and the lowest was –12.2°C at Hanmer Forest on the morning of 5 July.
  • Unusually warm in May, August, September, October and December.
  • Rather cool in January; July was the coldest in over 30 years.
  • Unusually wet with record low sunshine over the North Island in December.
  • The driest recorded centre was Alexandra, with only 299 mm of rain for the year.
  • North Egmont remained again being the wettest location with an annual total of 7546 mm. Milford Sound only managed 5134 mm in 2001.
  • Christchurch was the driest main centre with 405 mm and Auckland the wettest with 1256 mm. Wellington received 1053 mm and Dunedin 515 mm.
  • The capital was again the sunniest of the three largest centres with 2094 sunshine hours, followed by Christchurch (2072 hours), and Auckland (1981 hours). Nelson was the sunniest centre in 2001 with 2550 hours, followed by Blenheim with 2484 hours and Motueka with 2430 hours.

For further information, please contact:

Dr Jim Salinger – Principal Scientist, Climate
NIWA National Climate Centre – Auckland
Phone +64 9 375 2053
j.salinger@niwa.co.nz

Stuart Burgess – Climatologist
NIWA National Climate Centre – Wellington
Phone +64 4 386 0569
s.burgess@niwa.co.nz

Geoff Baird – Communications Manager
Phone +64 4 386 0543
g.baird@niwa.co.nz

Acknowledgement of NIWA as the source is required.

For more details read on

2001 – Extremely low annual rainfall in the eastern South Island and parts of the lower North Island, despite wet october–december conditions

Severe summer–autumn drought, big mid-winter freeze

Sunny in Nelson, Taranaki, Westland and Southland

The previous La Ni�a faded out in early 2001, and much more anticyclonic conditions than normal across the South Island for the first nine months of the year. This produced one of the driest years since records began in many eastern South Island areas. However, frequent troughs (‘lows’) in the Tasman Sea and over the North Island for the last three months produced a warm and wet end, especially for the North Island. Above average sea temperatures kept temperatures mainly higher than normal over land, and helped produce more stormy conditions from October to December.

2001 was also an extremely dry year in parts of Wellington. Rainfall was well below normal in southern Wairarapa, and below average in most other South Island areas. It was wetter than average in parts of Northland, Coromandel and Bay of Plenty. The severe summer–autumn drought was a major contributor to the extremely low South Island and southern North Island annual rainfall totals”.

The 2001 national average temperature, calculated by NIWA, was 12.8°C, which was 0.3°C above normal, according to NIWA. For New Zealand as a whole, there were eight warmer than average months (including five exceptionally warm months; May, August, September, October and December), and two very much cooler than average months (January and July). 2001 mean temperatures were average to above average in many areas for the year as a whole. However, they were below average in a few eastern districts. It was a sunnier than average year in Nelson, Westland, Taranaki, and Southland, but rather cloudy in eastern Bay of Plenty.

Pressures were higher than normal across the South Island, and the below average to the north of New Zealand, with more easterlies and north-easterlies onto the north, and more settled conditions elsewhere.

NOTE: throughout this report ‘normal’ refers to the 1961–1990 average

Sunny in Nelson, Taranaki, Westland and Southland

Low sunshine values in eastern Bay Of Plenty

2001 was a year with about 105 percent of normal sunshine recorded in Nelson, Taranaki, Westland and Southland. However, sunshine hours were well below average in Bay of Plenty. Near average sunshine hours occurred in other regions. Extremely low annual sunshine for the year 2001 were measured at:

Location

2001 sunshine
(hours)

Percentage of normal

Year records began

Comments

Whakatane

2051

88

1957

Lowest

Nelson was the sunniest centre in 2001, recording 2550 hours, followed by Blenheim with 2484 hours, and then Motueka with 2430+ hours. Total sunshine hours for the year 2001 in selected main centres were:

Location

2001 sunshine
(hours)

Normal
(hours)

Departure from normal

Comments

Auckland

1981

2043

–3%

Below average

Wellington

2094

2048

+2%

Near average

Christchurch

2072

2057

+1%

Near average

Dunedin

Not available

1613

 

Invercargill

1667

1565

+7%

Above average

Extremely low annual rainfall in the eastern South Island and Lower North Island

“NIWA figures show it was the one of the driest years since records began in many eastern South Island areas, as well as parts of Wellington. It was also a much drier than usual year in southern Wairarapa, and drier than average in most other South Island areas. Rainfall was above average in parts of Northland, Coromandel, and Bay of Plenty”, said Dr Salinger. The severe summer–autumn drought was a major contributor to the extremely low South Island and southern North Island annual rainfall totals”. Extremes of annual rainfall for the year 2001 were measured at:

Location

2001 rainfall
(mm)

Percentage of normal

Year records began

Comments

Wellington Airport

742

73

1960

2nd lowest

Hanmer Forest

681

59

1905

2nd Lowest

Waimate

336

53

1898

Lowest

Tara Hills

326

59

1950

Lowest

Wanaka Airport

514

73

1993

Lowest

Dunedin, Musselburgh

515

66

1918

2nd Lowest

Manapouri Airport

873

69

1992

Lowest

Lauder

384

78

1982

3rd lowest

Clyde

329

76

1984

3rd Lowest

Of the four main centres, Christchurch was the driest with 405 mm, and Auckland was the wettest with 1256 mm. Wellington received 1053 mm, and Dunedin 515 mm. Alexandra in Central Otago was the driest location NIWA measured in New Zealand, with only 299 mm. The wettest location in 2001, for which rainfall data are presently available, is North Egmont on the slopes of Mt Taranaki, with a total of 7546 mm. In comparison, Milford Sound received 5134 mm.

Slightly above average temperatures overall

The 2001 national average temperature, calculated by NIWA, was 12.8°C, which was 0.3°C above normal. For New Zealand as a whole, there were eight warmer than average months (including five exceptionally warm months: May, August, September, October and December), and two very much cooler than average months (January and July). Mean temperatures were about 0.5°C above average in parts of Auckland, Coromandel, Waikato, western Bay of Plenty, Wellington, and Nelson, and about 0.5°C below average in coastal areas of southern Hawke’s Bay, and parts of Central Otago. The warmest locale was Cape Reinga, with a mean temperature for the year of 16.9°C.

The highest extreme temperature for the year was 35.3°C recorded at Timaru Airport in very hot north-westerly conditions on 4 February. The lowest recorded temperature for the year was –12.2°C, measured at Hanmer Forest on the morning of 5 July.

Significant weather events – 2001

Five unusually warm months

Four of the eight warmer than average months, had unusually high mean temperatures (the national average temperature being in the top ten, since reliable records began in 1850s). December was very unusual, in that the overnight minima were extremely high. Comments on these are as follows:

May 7th warmest on record

Occasional summer-like temperatures occurred during the first two weeks when temperatures averaged 4°C above average, with many locations recording new extreme maximum May temperatures. Record high May extreme maximum temperatures were recorded at:

Location

Maximum temperature
(°C)

Date of occurrence

Year records began

Hokitika Airport

22.6

1

1964

Nelson Airport

22.0

3

1943

Auckland, Henderson

23.9

6

1986

Palmerston Nth. Airport

23.6

6

1962

Palmerston North

25.6

6

1918

Wellington Airport

22.0

6

1962

Kawerau

24.8

7

1954

Levin

22.9

11

1896

Wallaceville

23.3

11

1940

Arapito

23.6

11

1980

East Taratahi

23.7

12

1973

Near or record high mean temperatures (for the full month) occurred throughout much of the North Island, and many northern South Island regions, including parts of Central Otago and inland Southland. The national average temperature was 11.6°C, which was 1.1°C above the 1961–1990 normal, and 10th highest since reliable measurements began in the 1850s.

Unusually high mean May temperatures were recorded at:

Location

Mean temperature May 2001
(°C)

Departure from normal
(°C)

Year records began

Comments

Whangarei Airport

15.7

+1.7

1968

Highest

Auckland Airport

15.2

+1.8

1963

Highest

Paeroa

14.5

+2.7

1947

Highest

Tauranga Airport

14.6

+2.1

1913

2nd equal highest

Rotorua Airport

12.0

+1.6

1964

Highest

Taupo Airport

10.9

+2.1

1976

Highest

Hamilton, Ruakura

13.7

+2.2

1907

2nd highest

Hamilton Airport

13.3

+2.3

1971

Highest

New Plymouth

13.7

+1.7

1944

Equal highest

Turangi

11.1

+1.9

1968

Highest

East Taratahi

11.8

+1.9

1973

Highest

Palmerston Nth. Airport

12.8

+2.1

1962

2nd highest

Wellington, Kelburn

12.8

+1.6

1928

3rd highest

Wellington Airport

14.1

+2.1

1962

Highest

Wanganui

13.7

+1.7

1937

2nd highest

Farewell Spit

13.6

+1.8

1971

Highest

Nelson Airport

11.9

+2.0

1943

Equal highest

Chatham Islands

12.2

+1.8

1957

Highest

August 6th warmest on record

The national average temperature of 9.4°C was 0.8°C above the 1961–1990 normal, the highest for August since 1991 and 6th warmest since reliable measurements began in the 1850s. Near or record high mean August temperatures were recorded at:

Location

Mean temperature August
(°C)

Departure from normal
(°C)

Year records began

Comments

Wellington, Kelburn

10.3

+1.2

1862

3rd equal highest

Wallaceville

10.1

+1.7

1940

Highest

Nelson Airport

9.4

+1.5

1943

2nd highest

Blenheim

9.8

+1.2

1932

2nd equal highest

Chatham Islands

9.5

+1.0

1957

Equal highest

September 8th warmest on record

The national average temperature was 11.2°C, which was 0.9°C above the 1961–1990 normal, and 8th highest since reliable measurements began in the 1850s. Near or record high mean September temperatures were recorded at:

Location

Mean temperature September
(°C)

Departure from normal
(°C)

Year records began

Comments

Kaitaia Observatory

14.3

+1.4

1943

2nd equal highest

Hokitika Airport

10.9

+1.1

1867

4th equal highest

Milford Sound

10.0

+1.5

1935

Equal highest

Puysegur Point

11.1

+1.9

1978

Highest

Tara Hills

8.9

+1.9

1927

2nd equal highest

Dunedin, Musselburgh

10.7

+1.5

1853

2nd highest

Manapouri

8.8

+1.8

1992

Highest

Queenstown

10.1

+1.7

1871

2nd highest

Queenstown Airport

9.0

+1.7

1968

Highest

Clyde

10.4

+1.6

1983

Highest

Gore

9.8

+1.6

1930

2nd highest

Invercargill Airport

9.9

+1.6

1865

Equal highest

Tiwai Point

10.6

+1.7

1970

Highest

October 3rd warmest on record

This was the 3rd warmest October on record since reliable measurements began in the 1850s. The national average temperature of 13.4°C was 1.3°C above normal. The only other warmer Octobers were those of 1961 (13.8°C) and 1893 (13.7°C). Mean temperatures were much higher than usual in many North Island regions, as well as Nelson, and the South Island West Coast, being at least 1.5°C above normal. Near or record high mean October mean temperatures were recorded at:

Location

Mean temperature October
(°C)

Departure from normal
(°C)

Year records began

Comments

Kaitaia Observatory

15.8

+1.6

1985

Highest

Kerikeri

15.9

+1.7

1981

Highest

Whangarei Airport

16.5

+2.1

1967

Highest

Warkworth

15.3

+1.7

1972

2nd highest

Auckland, Owairaka

16.2

+2.1

1949

Highest

Auckland

16.2

+1.9

1868

Highest

Pukekohe

16.0

+2.6

1970

Highest

Paeroa

15.6

+1.7

1947

Equal highest

Tauranga Airport

15.5

+1.8

1913

Highest

Hamilton, Ruakura

15.1

+2.0

1907

Highest

Hamilton Airport

14.9

+2.1

1970

Highest

Turangi

13.3

+2.0

1968

Highest

Gisborne Airport

15.6

+1.8

1905

3rd highest

Palmerston North Air

14.0

+1.9

1962

Highest

Wallaceville

13.7

+1.9

1940

Equal highest

Farewell Spit

14.7

+2.1

1971

Highest

Westport Airport

13.9

+2.1

1937

Highest

Arapito

13.9

+1.9

1979

Equal highest

Hokitika Airport

13.1

+2.1

1866

Highest

Milford Sound

11.8

+1.7

1935

Highest

Nelson Airport

14.2

+2.0

1943

Highest

December Extremely high overnight minima

It was extremely warm throughout much of the North Island, due to well above average overnight temperatures. These were the highest on record throughout most of the North Island, and some South Island locations, with values between 2 and 3°C above average. Near or record high mean daily minimum December temperatures were recorded at:

Location

Mean daily minimum temperature

Departure from normal
(°C)

Year records began

Comments

Kaitaia Observatory

15.7

+2.2

1985

Highest

Kerikeri

15.0

+2.1

1945

Highest

Whangarei Airport

16.0

+2.2

1967

Highest

Auckland, Henderson

15.3

+2.7

1985

Highest

Auckland, Owairaka

16.1

+2.3

1949

Highest

Auckland Airport

16.5

+2.1

1962

Highest

Pukekohe

15.4

+2.8

1970

Highest

Paeroa

15.1

+2.7

1947

2nd highest

Tauranga Airport

15.7

+2.7

1913

Highest

Hamilton, Ruakura

14.6

+3.2

1906

Highest

Hamilton Airport

14.7

+4.1

1970

Highest

Whakatane Airport

15.5

+3.3

1974

Highest

Rotorua Airport

14.3

+3.0

1964

Highest

Taupo Airport

12.9

+2.6

1976

Highest

Taumaranui

13.9

+2.8

1947

Highest

New Plymouth Airport

15.0

+2.9

1944

Highest

East Taratahi

12.2

+2.8

1972

Highest

Gisborne Airport

15.2

+3.1

1905

Highest

Napier Airport

15.0

+2.4

1973

Equal highest

Napier, Nelson Park

15.8

+2.6

1870

3rd highest

Whakatu

14.1

+1.9

1982

Highest

Paraparaumu Airport

14.6

+2.5

1953

Highest

Palmerston North Airport

13.9

+2.7

1962

Highest

Levin

14.4

+2.4

1895

Highest

Wellington Airport

14.8

+1.6

1962

2nd highest

Normanby

13.9

+2.8

1977

Highest

Wanganui

15.0

+2.2

1937

Highest

Westport Airport

13.5

+2.2

1937

2nd highest

Hokitika Airport

12.6

+2.1

1963

3rd highest

Nelson Airport

14.1

+2.4

1943

Highest

Tara Hills

9.6

+2.0

1949

Highest

Dunedin Airport

10.4

+2.1

1962

2nd highest

Raoul Island

19.8

+1.7

1940

3rd highest

Chatham Islands

13.8

+2.9

1956

Highest

Low temperatures and snowfall

There were six significant cold periods during the tear, two with very extreme frosts and four with snowfall. The central North Island mid-August snowfall event was particularly severe.

January Rather cool

The national average temperature was 15.9°C, 1.2°C below the 1961–1990 normal. It was very much cooler than usual in Canterbury, Otago and Southland, with mean temperatures at least 1.5°C below average, the lowest for January in about 50 years in these regions. Inland areas of Otago were especially cool, with mean temperatures more than 2.5°C below average. Mean temperatures were 1.0 to 1.5°C below average throughout the remainder of the South Island, north Taranaki and Northland. Extremely low January mean temperatures were recorded at:

Location

January mean temperature
(°C)

Departure from normal
(°C)

Year records began

Comments

Christchurch Airport

15.2

–2.0

1954

2nd lowest

Lincoln

14.9

–1.9

1862

Lowest since 1930

Dunedin

13.3

–1.9

1853

Lowest since 1947

Lauder

13.7

–3.4

1925

Lowest

Clyde

15.2

–2.7

1984

Lowest

May Record screen frosts

Near or record low May screen frosts were measured at:

Location

Minimum temperature
(°C)

Date of occurrence

Year records began

Comments

Palmerston Nth. Airport

–3.4

29

1962

2nd lowest

Christchurch Airport

–5.3

26

1954

Lowest

Manapouri

–5.9

29

1962

Lowest

21–27 May Early snowfall

Waves of unseasonably cold southerlies from polar latitudes swept onto southern New Zealand, bringing hail and snow to sea level throughout Southland, and onto the south Otago high country from the afternoon of the 21st. Snowfall continued on the 22nd, lying to a depth of 2 cm along the coast and 8 cm in some inland areas. The cold blast continued on the 23rd, with snowfalls spreading north to the Dunedin hills, Westland and Banks Peninsula. Snowfall to 2.5 cm was measured at Okarito, Westland, an event unheard of before in that area. Snow depths to 5 cm were reported in the Catlins and as much as 20 cm in inland Southland and the Otago high-country. Further snowfall occurred in parts of Central Otago on the 27th.

10 June Snowfall

Bitterly cold southerlies brought snowfall (a few centimetres deep) to sea level in many eastern South Island regions on the 10th, especially in Southland and Otago, temporarily closing Dunedin’s northern motorway. Snow and ice also lay at the Rimutaka Hill summit north of Wellington, and closed the Desert Road.

July Very cold with severe frost

July had a prolonged very cold and frosty start over much of the South Island and many inland and southern North Island regions. The ground frosts were unusually severe at Hanmer Forest where there were 11 consecutive days with grass minimum temperatures below –10.0°C. These produced dangerous icy roads and numerous ice related accidents in many areas, frozen water supplies and water damage in buildings due to burst water pipes. Several small lakes and streams froze over for the first time in many years in some inland South Island regions.

Extremely low July grass minimum temperatures were recorded at:

Location

Grass minimum temperature
(°C)

Date of occurrence

Year records began

Comments

Auckland, Henderson

–7.3

12

1986

2nd lowest

Waiouru

–11.0

3

1962

Lowest

East Taratahi

–8.1

4

1972

Equal lowest

Paraparaumu Airport

–9.0

5

1953

2nd lowest

Wallaceville

–9.8

4

1940

Equal lowest

Hokitika Airport

–8.5

4

1971

2nd lowest

Motueka, Riwaka

–9.9

5

1956

3rd lowest

Appleby

–10.7

5

1932

2nd lowest

Nelson Airport

–9.7

4

1943

Equal lowest

Lake Rotoiti

–12.0

4

1966

Lowest

Reefton

–10.0

7

1961

3rd equal lowest

Hanmer Forest

–15.3

5

1930

Lowest

Arthurs Pass

–15.0

9 & 11

1978

Equal lowest

Culverden

–12.0

5

1983

Lowest

Winchmore

–12.4

5

1950

Lowest

Rangiora

–11.0

5

1965

Lowest

Christchurch Airport

–9.6

5

1954

Lowest

Waimate

–10.0

4

1918

3rd equal lowest

Dunedin Airport

–11.2

2 & 16

1963

3rd lowest

Ranfurly

–11.9

3

1975

2nd lowest

Lauder

–11.5

3

1982

3rd lowest

The July national average temperature of 6.8°C was 0.9°C below the 1961–1990 normal and the lowest for July since 1969. Near record low mean July temperatures were recorded at:

Location

Mean temperature July 2001
(°C)

Departure from normal
(°C)

Year records began

Comments

Taupo Airport

4.6

–1.5

1976

Lowest

Normanby

6.7

–1.9

1977

Lowest

Castlepoint

8.3

–1.7

1972

Lowest

East Taratahi

6.0

–1.3

1972

2nd lowest

Paraparaumu Airport

6.8

–1.7

1953

Lowest

Motueka, Riwaka

5.5

–1.4

1956

2nd lowest

Blenheim Airport

5.4

–1.5

1941

Lowest

Hanmer Forest

1.4

–2.7

1906

Equal lowest

Christchurch Airport

4.5

–1.3

1954

2nd equal lowest

Queenstown Airport

1.6

–1.6

1969

3rd lowest

Clyde

0.8

–2.5

1983

2nd equal lowest

28–29 July Significant alpine snowfall

Heavy snowfalls were recorded in most mountainous regions, and snow and ice closed Arthur’s Pass. Ruapehu ski field reported its largest snowfall in 20 years.

14–15 August Extensive central North Island snowfall

A severe mid-month storm produced extensive snowfall throughout the central North Island volcanic plateau, with depths of 30 cm at Ohakune, the town being isolated by snow-closed roads. Some of the roads that were closed due to snow and ice were: SH1 along the Desert Road – from the evening of the 14th through to the 16th, SH4 from Raetihi to National Park, SH49 from Waiouru to Ohakune and from Ohakune to Raetihi, and SH5 between Taupo and Napier. Snow also lay (few cm deep) at Mangaweka. The snowfall (20 cm) at Waiouru was reported as being the “biggest and deepest since 1974”.

Drought and record low monthly rainfall

January

January began with a continuation of severe soil moisture deficits in Marlborough and the development of similar conditions in Nelson, north Canterbury and south of Napier. Significant soil moisture deficits also developed throughout Auckland, Waikato, Bay of Plenty, and the southern half of the North Island, and from Nelson to Otago. These conditions reflected the very dry conditions that prevailed in many areas with rainfall less than a quarter of normal in Wellington, Nelson and Marlborough, and half of normal in many other areas.

February

Severe soil moisture deficits continued in Marlborough, Nelson, Canterbury and Wellington, with extreme or very high fire risk. Severe soil moisture deficits extended from Nelson through to North Otago in the South Island, and spread to the Wairarapa in the North Island. Rainfall was below average over the entire South Island, especially in Marlborough, Nelson and Canterbury where totals were much less than 25 percent of normal. It was also very much drier than average in Buller, north Otago and Wellington, with rainfall 50 percent or less than normal. Blenheim’s 2-month rainfall total was only 8 mm; the 2nd lowest for any January through February period there in records going back to 1930. Only 1939 was drier.

March

Virtually no rainfall occurred in many areas of the South Island from Golden Bay across to Nelson, and Marlborough to Southland. Many sites in Canterbury and Otago measured totals of 5 mm or less. Severe soil moisture deficits continued in Marlborough, Nelson, Canterbury and Wellington accompanied by very high or extreme fire risk. The lack of rainfall extended the severe soil moisture deficits in the north and east of the South Island from Nelson to Otago, and these spread to central Hawke’s Bay in the North Island. Rainfall totalled at least 300 mm in the Southern Alps between the 26th and 28th, recharging alpine rivers and bringing some relief to parched east coast areas downstream. However, rivers further east remained at record low levels, with some completely dry. Near or record low rainfall was measured in many areas from Golden Bay across to Nelson, and from Marlborough to inland Southland, with totals much less than 25 percent of normal at most locations. Rainfall was also extremely low in Auckland, and parts of western Northland, with rainfall 25 percent or less of normal. Waikato, eastern Bay of Plenty, Gisborne, central Wairarapa, southern Buller, southern Buller, Westland and the Southern Alps received near normal rainfall. For the year to date, the Wellington January–March total of 61 mm is the lowest since records began in 1862, and the Blenheim 3-month total of 20 mm the 2nd lowest in records going back to 1902.

April

Very low rainfall occurred in many South Island areas, especially in the east from the Marlborough coast to Otago, with most sites recording less than 25 percent of normal. Many sites in Canterbury and Otago measured rainfall totalling 15 mm or less for the second consecutive month. Severe soil moisture deficits continued in Canterbury, Otago, and parts of Marlborough. East coast rivers remained at abnormally low levels. Rainfall was also extremely low in Wellington where it was less than 20 percent of normal. Significant soil moisture deficits persisted in Wellington and extended into Wairarapa. Of special note, rainfall for the year to date was the lowest in more than 100 years in both Wellington (77 mm), and Christchurch (60 mm), and the lowest in more than 60 years throughout much of Nelson and Marlborough (Blenheim measured only 38 mm). At the same time as the east had been extremely dry, it was also one of the driest in almost 40 years of measurement at Hokitika.

May

Soil moisture conditions were still unusually dry for the time of year in Marlborough, north and central Canterbury, where they were still in moderate to severe deficit. Low rainfall occurred in Marlborough, with totals about 50 percent of normal.

June

Soil moisture conditions were still low for the time of year in parts of north Otago.

August

Rainfall in parts of Canterbury and north Otago was well below average, being 50 percent or less than normal. It was also below average in the Waitaki and Clutha lakes catchments. Soil moisture continued lower than normal in central Marlborough, around Christchurch and north Canterbury, and in north and central Otago.

September

Rainfall was extremely low throughout much of the south and west of the North Island, as well as Nelson, Marlborough, Canterbury, and Otago, all recording less than 25 percent of normal, with totals of less than 20 mm. Near or record low rainfall was measured at many locations within these regions. Soil moisture deficits were significant for the time of year in central Marlborough, around Christchurch and north Canterbury, and north and central Otago.

October

Only half the normal rainfall occurred in the Southern Lakes. Soil moisture deficits remained very high for the time of year in inland areas of both Otago and south Canterbury.

Record low monthly rainfall

Some locations measured extraordinary low rainfall at various times during the year. These were:

Location

Rainfall
(mm)

Percent of normal

Year records began

Comments

January

Levin

12

14

1896

2nd lowest

Kelburn, Wellington

13

16

1862

5th lowest

Wellington Airport

7

10

1960

Lowest

Wallaceville

20

23

1924

Lowest

Blenheim

2

6

1930

2nd equal lowest

Blenheim Airport

5

9

1941

3rd lowest

Febuary

Westport Airport

39

28

1945

Lowest

Lake Rotoiti

7

7

1934

Lowest

Moteuka, Riwaka

2

3

1943

2nd lowest

Nelson Airport

6

11

1941

3rd equal lowest

Blenheim Airport

3

9

1941

4th lowest

Hanmer Forest

7

10

1905

2nd lowest

Kaikoura

13

24

1950

2nd lowest

Winchmore

11

20

1947

2nd lowest

Christchurch Airport

4

10

1944

Lowest

Christchurch Gardens

4

10

1864

3rd equal lowest

Timaru Airport

9

19

1957

Lowest

Waimate

10

20

1898

Equal lowest

Manapouri

15

19

1914

3rd lowest

March

Dargaville

17

19

1943

Equal lowest

Auckland, Owairaka

13

13

1949

Lowest

Waiouru

22

27

1961

2nd lowest

Blenheim Airport

8

13

1941

3rd lowest

Winchmore

4

7

1947

Equal lowest

Lincoln

4

7

1881

Lowest

Akaroa, Rue Lavaud

3

3

1978

Lowest

Timaru Airport

4

8

1957

Lowest

Tara Hills

1

3

1950

Lowest

Dunedin Airport

8

12

1963

Equal lowest

Musselburgh

2

3

1918

Lowest

Gore

18

22

1943

2nd lowest

April

Cape Palliser

5

6

1930

Lowest

Wellington, Kelburn

16

15

1862

Equal lowest

Wellington Airport

11

13

1960

2nd lowest

Westport Airport

53

28

1944

2nd lowest

Hanmer Forest

20

19

1905

3rd lowest

Christchurch Airport

7

13

1944

Lowest

Christchurch Gardens

5

8

1864

2nd lowest

Lincoln

5

8

1881

Lowest

Akaroa, Rue Lavaud

12

14

1978

Lowest

Musselburgh

21

32

1918

3rd lowest

Queenstown Airport

11

20

1969

Lowest

June

Kerikeri

59

33

1936

3rd lowest

Whangarei Airport

39

22

1937

2nd lowest

Mokohinau Island

21

16

1935

Lowest

Warkworth

75

42

1972

Lowest

Whitianga

45

24

1942

2nd equal lowest

Te Puke

64

35

1973

Lowest

Whakatane Airport

44

36

1975

Lowest

July

Westport Airport

36

19

1944

Lowest

Lake Rotoiti

15 to 30

12

1934

Lowest

Hokitika

28

12

1866

Lowest

Motueka

36

23

1943

2nd lowest

Nelson Airport

8

9

1941

Lowest

Blenheim Airport

12

17

1941

Lowest

Tara Hills

3

9

1950

Lowest

Manapouri

28

31

1991

Lowest

September

Pukekohe

48

39

1970

Lowest

Taupo Airport

19

25

1976

Lowest

Taumarunui

19

13

1913

Lowest

Turangi

44

31

1968

Lowest

Ohakune

9

7

1975

Lowest

Waiouru

20

22

1950

Lowest

Wanganui

5

7

1890

Lowest

Palmerston N Airport

12

15

1943

Lowest

Levin

9

10

1895

Lowest

Waione

0

0

1992

Lowest

East Taratahi

16

18

1972

Lowest

Palliser

9

12

1930

Lowest

Paraparaumu Airport

16

19

1945

Lowest

Wallaceville

10

10

1924

Lowest

Wellington Airport

8

9

1960

Lowest

Lake Rotoiti

32

23

1934

Lowest

Nelson Airport

21

26

1941

3rd lowest

Blenheim

13

28

1930

3rd lowest

Blenheim Airport

11

18

1941

3rd lowest

Hanmer Forest

10

11

1905

Lowest

Floods and high rainfall

There were at least ten high-rainfall/flood-producing events during 2001. These were most frequent in the North Island. The most significant episodes are listed below.

11 & 17 February

High rainfall occurred in Coromandel on the 11th, Whitianga recorded 120 mm. Further high rainfall occurred in Bay of Plenty and Gisborne on the 17th, Whakatane recording 130 mm.

12–13 April

The remnants of tropical cyclone ‘Sose’ produced high rainfall in the Bay of Islands, Coromandel, and Bay of Plenty over the night of 12/13 April. Significant surface flooding resulted in Keao where rainfall totalled 200 mm in less than 18 hours, and at Whitianga where 132 mm was measured in 24 hours.

2 May

High intensity rainfall resulted, within a few hours, in widespread surface flooding and created chaos for Auckland traffic on 2 May. Water, in places, on the southern motorway was as high as car bonnets, bringing traffic to a stop. Rainfall totalling 30 mm was recorded at Whangaparoa in the hour to 5pm.

12 May

Heavy rainfall and surface flooding occurred on 12 May in Auckland, the Nelson-Takaka, and eastern Bay of Plenty-Opotiki/Ohopi areas (where rainfall as high as 60 mm in 3 hours was reported).

30 May

Extreme high intensity rainfall occurred at Leigh (north of Auckland) on 30 May. Torrential rainfall totalling 109 mm was measured in just one hour (between 1.30 and 2.30 am), superseding the previous non-mountainous New Zealand record for a one-hour event of 107 mm measured at Whenuapai on 16 February 1966. There was widespread damage to local roads, problems with drainage systems, and water flowed on torrents over an already saturated ground surface.

30–31 August

Heavy rainfall, totalling as much as 150 mm, was reported in the Coromandel over the night of 30th/31st August. It was also very wet, with totals ranging from about 50–100 mm, throughout Auckland.

1 & 5 September

High intensity rainfall occurred in Warkworth on the 1st, with totals of 36 mm in one hour, 57 mm in two hours, and 154 mm in 24 hours. Further heavy rainfall, with surface flooding occurred throughout Northland on the 5th, with rain as high as 25 mm in an hour, and temporary closure of a number of roads. Many sites in the region measured rainfall totalling between 75 and 100 mm in the 24 hours to 9 am on the 5th. Heavy rainfall and surface flooding also occurred in the Auckland region.

9–10 October

Heavy rainfall at Whakatane totalled 101 mm for the 24 hours to 9 am on the 10th.

22 November

High rainfalls resulted on the 22nd with totals from 50 to 100 mm throughout the Wellington-Hutt Valley region (where a few slips and surface flooding resulted, causing some road closures and traffic delays). Water was knee-high on a Newlands Road. Much of the Wellington rainfall occurred within six hours.

2 December

High rainfall occurred throughout Northland. The Awanui River peaked 7 metres above normal, blocking off parts of SH 12 due to flooding.

Record high monthly rainfall

Some locations experienced extraordinary high rainfall at various times during the year. These were:

Location

Rainfall
(mm)

Percent of normal

Year records began

Comments

February

Whitianga

270

281

1942

2nd highest

Tauranga Airport

268

325

1898

2nd highest

Whakatane

310

426

1992

Highest

April

Kerikeri Airport

383

320

1978

2nd highest

Tauranga Airport

348

359

1898

2nd highest

Whakatane

233

314

1992

Highest

May

Cape Reinga

202

231

1920

3rd highest

Warkworth

368

304

1972

Highest

Auckland Airport

210

211

1962

Highest

Whitianga Airport

331

229

1991

Highest

Waihi

500

285

1889

2nd highest

Rotorua Airport

335

297

1964

Highest

Taupo Airport

139

201

1976

Highest

October

Te Paki, Far North

201

275

1931

Highest

Palmerston N. Airport

137

190

1943

2nd highest

Appleby

219

243

1932

2nd highest

Nelson Airport

286

321

1941

Highest

Blenheim Airport

178

278

1941

Highest

Blenheim Research

161

286

1930

Highest

November

Paraparaumu Airport

168

205

1945

3rd highest

December

Kerikeri Airport

270

247

1978

Highest

Manukau Heads

174

207

1935

2nd highest

Motu

449

261

1990

Highest

New Plymouth Airport

346

318

1944

2nd highest

Taumarunui

308

225

1913

2nd highest

Turangi

314

246

1968

Highest

Castlepoint

165

258

1902

3rd highest

East Taratahi

137

253

1972

Highest

Napier Airport

188

254

1950

2nd highest

Napier, Nelson Park

172

259

1870

2nd highest

Whakatu

143

467

1982

Highest

Mahia

165

255

1990

Highest

Wanganui

173

224

1890

2nd highest

Wellington Airport

134

181

1960

2nd highest

Lake Rotoiti

324

220

1933

Highest

Reefton

335

197

1904

2nd highest

Tornadoes, gales and high winds

16 January

Winds gusting to 170 km/h, recorded at Taiaroa Head, Otago Harbour, lashed the South Island on 16 January, causing power blackouts, blew fruit off trees in Central Otago and yachts off their moorings. Wellington was also battered by winds up to 140 km/h, lifting roofs and bringing down power lines. A wind gust of 161 km/h was recorded at Puysegur Point, at the southwest tip of the South Island.

28–29 March

A tornado, with severe winds, ripped through part of Greymouth at about 4 am on the morning of 28 March. Several houses and garages were badly damaged by the wind and flooded by heavy rainfall accompanying the tornado. High winds from the northwest, gusted to 143 km/h in Kaikoura over the night of 28/29 March, damaging power lines resulting in loss of electricity to more than 300 houses. An injured passenger was airlifted from a boat in Foveaux Strait in rough conditions on the same night.

4–5 May

High winds buffeted western Bay of Plenty over the night of 4/5 May, with a tree uprooted and power lost to parts of Tauranga. One house lost part of its roof.

10 June

Southerly gales affected Cook Strait, disrupting ferry services.

28–29 July

High winds and heavy seas buffeted southern and eastern coasts on the 28th and 29th, with 11-metre swells in Cook Strait. One of the Cook Strait fast ferries was forced to turn back to Wellington, with many other ferry sailings cancelled, disrupting thousands of passengers.

14–15 August

A depression developed on a southerly front on the 14th, deepening later just east of Gisborne. The associated weather system produced southerlies of violent-storm force (mean wind speeds to 117 km/h, and gusts to 189 km/h) in Cook Strait, with huge swells and 11-metre waves. These resulted in the cancellation of ferry crossings on the 15th.

23 August

High winds, reported to be those of a tornado or waterspout, lifted a garage roof and caused damage to trees and fences from Katikati to Omokoroa (western Bay of Plenty). The severe winds at Omokoroa (at 7.15 pm) lasted less than a minute. Parts of a fence were later found more than 100 metres away. The damaging winds were followed about 45 minutes later by thunder, lightning, heavy rainfall and hail.

9 October

High winds occurred with the passage of a 100-metre-wide waterspout/tornado through Cable Bay, Northland, at about 12.30 pm on the 9th, resulting in damage to about 19 houses, some extensive. Another tornado was report on the same day, at Mata, 22 km southeast of Whangarei, moving a barn 100 metres across a paddock.

22 October

High winds and heavy rainfall buffeted the Gisborne region over the night of the 22nd, resulting in extensive damage in kiwifruit orchards.

31 October

Squally north-westerlies with isolated thunderstorms and heavy rainfall affected many northern and western North Island regions, with the approach of an active cold front, during the night of 31 October. Parts of Auckland appeared to be worst affected with fallen trees, and at least 10 houses having damaged roofs, associated with the passage of a ‘vortex’ and wind gusts to about 150 km/h. Fallen trees were also reported in Tauranga and Rotorua.

4 November

Four tornadoes were sighted at Awakeri, near Whakatane; one totally destroyed a shed on a farm, just missing nearby residents.

17 November

Storm-force southerlies buffeted Cook Strait, with wind gusts to 198 km/h at Baring Head.

Severe or damaging hail storms

7–8 January

A sudden and violent hailstorm, lasting about 10 minutes occurred in the Masterton area about 6 pm on 7 January. Hailstones, some the size of golf balls (up to 4 cm in diameter) were reported. On two orchards all the apple and pear crops were lost, with severe damage to fruit in others. Over half the grapes were lost in one orchard. The severe hailstorm also broke windows and skylights, and damaged cars. The overall estimate of losses is $5 million. Golf ball-size hailstones were reported at Alexandra on 8 January, causing significant damage to some cherry crops.

28 December

Hail lay 4 cm deep in parts of Rangiora following a convectional storm during the afternoon.

Sunshine extremes

Some locations incurred extremes of sunshine hours at various times during the year. These were:

Location

Sunshine Total
(hrs)

Percent of normal

Year records began

Comments

March

Wellington, Kelburn

248

134

1928

Highest

Nelson Airport

279

137

1949

Highest

Invercargill Airport

178

135

1932

2nd highest

May

Whakatane

114

67

1957

Lowest

Queenstown

62

70

1930

3rd lowest

July

New Plymouth

195

144

1915

2nd highest

Hokitika

193

160

1913

2nd highest

Nelson Airport

207

134

1949

2nd highest

October

New Plymouth Airport

149

79

1973

Lowest

Wellington, Kelburn

125

64

1928

2nd lowest

Christchurch Airport

143

70

1949

Equal lowest

November

Whakatane

163

74

1957

3rd lowest

Blenheim

183

78

1930

3rd lowest

December

Kaitaia Observatory

163

75

1985

Equal lowest

Whakatane

135

59

1957

Lowest

Taumarunui

111

58

1947

Lowest

New Plymouth Airport

165

71

1972

Lowest

Paraparaumu Airport

135

60

1953

Lowest

Wellington, Kelburn

153

62

1928

2nd lowest

Hokitika Airport

123

63

1964

Lowest

Nelson Airport

164

68

1948

Lowest

For further information, please contact:

Dr Jim Salinger – Principal Scientist, Climate
NIWA National Climate Centre – Auckland
Phone +64 9 375 2053
j.salinger@niwa.co.nz

Stuart Burgess – Climatologist
NIWA National Climate Centre – Wellington
Phone +64 4 386 0569
s.burgess@niwa.co.nz

Geoff Baird – Communications Manager
Phone +64 4 386 0543
g.baird@niwa.co.nz

Acknowledgement of NIWA as the source is required.