Winter 2007

Winter 2007: Rainfall and temperature contrasts, with floods, windstorms and tornadoes.

  • Rainfall: Well above normal in parts of Northland, Hawke’s Bay, and Otago, well below normal in Nelson, and inland parts of Marlborough and Canterbury
  • Temperature: Above average throughout the northern half of the North Island, below average over the southern half of the South Island
  • Sunshine: Well above normal in Otago and inland South Canterbury

The winter of 2007 had contrasts in rainfall and temperature, with significant extremes. There were serious flood producing rainfall events in Northland, Hawke’s Bay, and Otago. Whangarei had its wettest winter since 1973, Nelson experienced its driest winter since 1987, and extended periods of severe frost occurred in Otago. An unprecedented swarm of damaging tornadoes affected Taranaki over 4-5 July. Other windstorms also damaged property and affected infrastructure.

Seasonal rainfall was more than 150 percent (one and a half times) of normal in some eastern areas of Northland, central parts of Hawke’s Bay, and in North Otago. In contrast, rainfall was less than 50 percent (half) of normal in inland areas of Marlborough, and parts of Banks Peninsula. Moderate soil moisture deficits, although not severe, existed at the end of winter in many eastern regions from Marlborough to Central Otago. Winter, overall, was warmer than normal throughout the northern half of the North Island, where temperatures were 1°C above average. However, temperatures were more than 1.0 °C below average in some inland parts of Otago, and also below average in inland areas of south Canterbury and Southland. The national average temperature of 8.5 °C was exactly normal. Sunshine hours were well above normal in Otago and inland areas of South Canterbury. Totals were below normal in the Wairarapa. The overall winter climate pattern was dominated by more depressions (‘lows’), often centred southeast of the South Island, with more frequent southerly flow over the South Island and lower half of the North Island, and more westerlies further north.

Major Highlights

  • The highest temperature recorded during the winter was 22.4 °C recorded at Rangiora on the 1 June. The lowest air temperature for the winter was -15.4 ºC recorded at Lauder on 18 July, the lowest there since July 1995. Many other inland South Island locations recorded minimum air temperatures below -10.0 ºC during July, often accompanied by freezing fog and treacherous ice.
  • There were two major snowfall events, both affecting Southland and Otago. The first over 7-9 June and the second over 20-24 June, also affecting Reefton on the West Coast.
  • Heavy rainfall produced widespread severe flooding and landslips throughout much of Northland on 10 July, the town of Kaeo being worst hit, and Whangarei was completely blocked off by floodwaters and slips. Flooding also occurred near Hastings on 17 July, and along the south Canterbury-Otago coast on 30 July.
  • An unprecedented number of several damaging tornadoes affected parts of the north and west of the North Island over 4-5 July, with damage being particularly severe in Taranaki. The township of Oakura was severely affected, with a substantial number of houses damaged. Another small tornado occurred near New Plymouth, tipping a truck and trailer unit on its side, on 31 July.
  • The flood producing event of 10 July also produced damaging easterly gales, resulting in fallen trees, broken power lines, and other damage in Northland, Auckland, and Coromandel, leaving more than 140,000 people without electricity. More gales over 11-12 August, this time from the northwest, buffeted many central and southern New Zealand regions, with damaged power lines in parts of Otago.
  • Of the five main centres, Auckland was the warmest and wettest, and Christchurch the driest, sunniest and coldest.

Rainfall

Winter rainfall was more than 150 percent (one and a half times) of normal in some eastern areas of Northland, central parts of Hawke’s Bay, and in North Otago, and also above normal in the north of Northland, as well as Thames, Coromandel, and East Otago. In contrast, rainfall was less than 50 percent (half) of normal in inland areas of Marlborough, and parts of Banks Peninsula, and also below normal in Wairarapa, Nelson, many inland areas of Canterbury.

Temperature

Seasonal mean temperatures were above average throughout the northern half of the North Island and 1.0 °C above average in parts of Northland and Gisborne. In contrast, they were more than 1.0 °C below average in some inland parts of Otago, and also below average in inland areas of south Canterbury and Southland. The national average temperature of 8.4 °C was 0.1°C below normal.

Sunshine

Winter sunshine hours and/or solar radiation were at least 115 percent of normal in Otago, inland areas of South Canterbury, Westland, and Southland. Sunshine hours were below normal in the Wairarapa.

Full report

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.