August 2003
Monday, 1 September 2003
Sunshine: Well above average in Southland and Westland
Rainfall: Less than half average in many inland and western regions, especially Manawatu, Horowhenua, and inland south Canterbury; wet in some areas exposed to the east, especially central Hawke’s Bay
Temperatures: Average or above average temperatures in many areas, colder in parts of Central and South Otago
August was more settled, and much drier than average in many inland and western regions, with wetter than usual conditions in some areas exposed to the east, and colder than usual conditions in parts of Central and South Otago. The August climate patterns were associated with more anticyclones (‘highs’) than average well southeast of the South Island, and more depressions (‘lows’) than average northeast of the North Island, four of which affected the North Island during the month. These produced more frequent easterlies over the North Island, and northeasterlies over the South Island.
Highlights
- August 2003 temperatures ranged from a low of –7.5°C, recorded at Ranfurly on the 24th, to a high of 22.1°C, recorded at Darfield on the 26th.
- Severe overnight ground frosts occurred at Ettrick (–12.2°C) on the 14th, and –10 to –12C° in several inland areas of Canterbury and Otago on the 24th.
- Heavy rainfall occurred in Northland, Coromandel and along the southern Wairarapa coast over 21–22 August.
- Cold southeasterlies brought snowfall settling down to 400–500 m in Canterbury and Otago from the 11–13, and 20–22 August.
- Dunedin and Christchurch were the driest of the four main centres, and Auckland the sunniest. August rainfall was below average in Auckland, Christchurch, and Dunedin, and near average in Wellington. Mean temperatures were above average in Auckland and Wellington, and near average in the other two centres. Sunshine hours were near average in all four centres.
Rainfall
It was more settled for the time of year, with less than 50 percent (half) of average throughout much of Waikato, inland Bay of Plenty, King Country, Taupo–Tongariro, the central North Island Plateau, Wanganui, Manawatu, Horowhenua, Kapiti, and inland south Canterbury. Rainfall was also below average in Nelson, central Marlborough, and the remainder of Canterbury, as well as coastal Otago. Totals were above average in many North Island areas exposed to the east, as well as the Kaikoura Coast, and parts of Central Otago.
Temperatures
Mean temperatures were near or above average in the North Island and much of the South Island, but below average in parts of Central and South Otago where they were more than 1.0°C below normal. The August national average temperature of 9.0°C was 0.4°C above normal.
Sunshine
Sunshine totals were well above average in Southland and Westland, below average in Northland, and near average in most other regions.
Below average rainfall in many inland and western regions
Above average rainfall in some eastern regions
Rainfall was less than 50 percent (half) of average throughout much of Waikato, inland Bay of Plenty, King Country, Taupo–Tongariro, the central North Island Plateau, Wanganui, Manawatu, Horowhenua, Kapiti, and inland south Canterbury. Totals were less than 75 percent (three-quarters) of average throughout Nelson, central Marlborough, the remainder of Canterbury, as well as coastal Otago. Rainfall was near average in much of Wairarapa, south Westland, Fiordland, and Southland.
In contrast, it was unsettled with rainfall at least 120 percent of average in some areas exposed to the east, including, much of Northland, Coromandel, Gisborne, Hawke’s Bay, southern coastal Wairarapa, and the Kaikoura Coast, as well as parts of Central Otago.
Near or record low August rainfall was recorded at:
| Location | August rainfall (mm) | Percentage of normal | Year Records began | Comments |
|---|---|---|---|---|
| Matamata, Hinuera | 46 | 35 | 1966 | 2nd lowest |
| Auckland Airport | 52 | 47 | 1962 | 3rd lowest |
| Pukekohe | 24 | 21 | 1970 | Lowest |
| Hamilton, Ruakura | 45 | 39 | 1905 | 2nd equal lowest |
| Hamilton Airport | 32 | 28 | 1935 | Lowest |
| Turangi | 50 | 33 | 1968 | Lowest |
| Paraparaumu Air. | 35 | 36 | 1945 | Well below average |
| Palmerston N. Air. | 20 | 25 | 1943 | Lowest |
| Levin | 19 | 20 | 1895 | Lowest |
| Wanganui | 20 | 28 | 1890 | 3rd equal lowest |
| Tara Hills | 4 | 8 | 1985 | Well below average |
| Wanaka Airport | 19 | 33 | 1992 | Lowest |
| Campbell Island | 37 | 36 | 1941 | Lowest |
| Chatham Is | 21 | 26 | 1951 | Lowest |
Near or record high August rainfall was recorded at:
| Location | August rainfall (mm) | Percentage of normal | Year Records began | Comments |
|---|---|---|---|---|
| Napier Airport | 151 | 201 | 1950 | Well above average |
| Palliser, Ngawihi | 231 | 210 | 1989 | Highest |
| Whakatu | 153 | 259 | 1983 | 2nd highest |
Average or above average temperatures in many areas
Colder in Central and South Otago
Mean temperatures were at least 0.5°C above average in parts of Auckland, Waikato, Taranaki, the Central North Island Volcanic Plateau, Wellington, Nelson, and south Westland. However, they were 1.0°C or more below average in parts of Central and South Otago. Elsewhere they were near average.
Near or record mean August temperatures were recorded at:
| Location | Mean temperature | Departure from average (°C) | Records began | Comments |
|---|---|---|---|---|
| Farewell Spit | 11.2 | +1.5 | 1971 | 3rd equal highest |
| Puysegur Point | 10.0 | +1.6 | 1980 | Highest |
| Clyde | 4.4 | –1.3 | 1983 | Equal lowest |
Rather sunny in Southland
Sunshine totals were well above average (at least 120 percent of normal) in Southland, and above average (at least 110 percent of normal) in Buller and Westland. Sunshine was below average in Northland, and near normal in most other regions.
Well above average August sunshine hours were recorded at:
| Location | August sunshine (hours) | Percentage of normal | Year Records began | Comments |
|---|---|---|---|---|
| Invercargill Airport | 161* | 134 | 1932 | 3rd highest |
* estimated (missing 2 days)
August climate in the four main centres
Of the four main centres, Christchurch and Dunedin were the driest, both with 33 mm. Rainfall was also below average in Auckland. August rainfall was near average in Wellington. Mean temperatures were above average in Auckland and Wellington, and near average in the other two centres. Sunshine hours were near average in all four centres, of which Auckland was the sunniest.
| Auckland* | Wellington | Christchurch | Dunedin | |
|---|---|---|---|---|
| August mean temp. (°C) |
11.7 | 9.7 | 7.7 | 7.5 |
| Dep. from normal (°C) |
+0.5 | +0.6 | –0.1 | 0.0 |
| Above average | Above average | Near average | Average | |
|
|
||||
| August rainfall (mm) | 98 | 150 | 33 | 33 |
| % of normal | 73 | 111 | 52 | 56 |
| Below average | Near average | Below average | Below average | |
|
|
||||
| August sunshine (hours) | 149* | 133 | 144 | 125 |
| % of normal | 102 | 106 | 99 | 109 |
| Near average | Near average | Near average | Near average | |
aMt Albert, * Estimated from solar radiation
Highlights and extreme events
- August 2003 temperatures ranged from a low of –7.5°C, recorded at Ranfurly on the 24th, to a high of 22.1°C, recorded at Darfield on the 26th.
- Severe overnight ground frosts occurred at Ettrick (–12.2°C) on the 14th, and of –10 to –12°C in several inland areas of Canterbury (Mt Cook Village) and Otago (Ranfurly) on the 24th.
- Near or record low grass minimum August temperatures were recorded at:
Location Grass min. (°C) Date Records began Comments Ettrick –12.2 14th 1985 2nd lowest Ranfurly –10.5 24th 1975 3rd lowest - Heavy rainfall occurred in Northland, Coromandel and along the southern Wairarapa coast over 21–22 August. Whitianga Airport recorded rainfall totalling 109 mm for the 24 hours to 2 am on the 21st. Palliser, Ngawihi recorded rainfall of 105 mm for the 24 hours to 2 am on the 22nd.
- Cold southeasterlies brought snowfall settling down to 400–500m in Canterbury and Otago from the 11th to the 13th, and 20th to 22nd.
For further information, please contact:
Dr Jim Salinger – Principal Scientist, Climate
NIWA National Climate Centre – Auckland
Phone +64 9 375 2053
[email protected]
Stuart Burgess – Climatologist
NIWA National Climate Centre – Wellington
Phone +64 4 386 0569
[email protected]
Geoff Baird – Communications Manager
Phone +64 4 386 0543
[email protected]
Acknowledgement of NIWA as the source is required.