January 2007

• Rainfall: Below normal in many regions, areas of above normal rainfall in Northland, Bay of Plenty, Taupo, near East Cape, Wellington, and Nelson
• Soil moisture: Severe deficits in Auckland, Nelson, eastern regions from Gisborne to Marlborough, and Central Otago
• Temperature: Above average in the east of the North Island and on the South Island’s West Coast; below average in the east of the South Island
• Sunshine: Below normal in many regions, sunny in Southland

January was generally cloudy with low rainfall over much of New Zealand, and east-west temperature contrasts.

Rainfall was below average in many regions, especially in the east where totals were 50 percent (half) or less of normal. Areas with above normal rainfall occurred in Northland, Bay of Plenty, Taupo, near East Cape, Wellington, and Nelson. Offshore, rainfall was more than 200 percent (twice) of normal in the Chatham Islands. Significant soil moisture deficits (of at least 110 mm) occurred during January throughout much of Auckland, Waikato, Bay of Plenty, Nelson, and eastern regions of both islands. However, deficits were severe (at least 130 mm) in Auckland, Nelson, eastern regions from Gisborne to Marlborough, and Central Otago. Below average temperatures persisted (from December) in January in the east of the South Island. However, temperatures were above average for the time of year in Gisborne, Hawke’s Bay, on the South Island’s West Coast, and in the Southern Lakes district. Temperatures, especially in the south and east, were well below normal during the first week of the month, but more typical of summer in many regions after that. The national average temperature was 16.7 °C (0.4 °C below normal). Sunshine hours were below normal in many regions, but above normal in Southland. More anticyclones (‘highs’) predominated south of New Zealand, with troughs of low pressure often over central New Zealand. As a result, southeasterlies were more frequent than average over much of the South Island, while more frequent westerlies prevailed north of the country.

Other Highlights

• The lowest air temperature during January 2007 was -0.6 °C recorded at Waiouru on the 4th.
• The highest temperature during the month was 33.5 °C recorded at Napier Airport on the 22nd, with maximum temperatures between 30.0 °C and 33.0 °C measured on the same day at many other eastern localities from Gisborne to Otago.
• There were several high rainfall events, with at least 50 mm in 24 hours, most of which affected the South Island’s West Coast (on the 6th, 13th, 20th, 22nd, 29th, and 31st). However, high rainfall (about 60 mm) occurred in parts of Coromandel and Bay of Plenty on the 9th, and Northland (55-60 mm) on the 12th.
• A wind gust of 167 km/h from the northwest was recorded at Rock and Pillar, Otago, on the22nd.
• Auckland was the warmest and sunniest, Christchurch the driest, and Wellington the wettest of the five main centres. Temperatures were above normal in Hamilton, and below normal in the other main centres, especially Christchurch. Rainfall was above normal in Wellington, near normal in Hamilton, and below normal in Auckland, Christchurch and Dunedin. Sunshine hours were near normal in Auckland, but below normal in the other main centres.

Rainfall

January rainfall totals were 50 percent (half) or less of normal throughout much of Hawke’s Bay, Canterbury, and Otago. Rainfall was also below average throughout much of Wairarapa, Westland, and Southland. Rainfall was above average, with totals 125 percent (one and a quarter) or more of normal, in parts of Northland, Bay of Plenty, Taupo, near East Cape, Wellington, and Nelson.

Temperature

Mean temperatures were below average in many eastern regions from Wairarapa to Otago. However, they were more than 1.0 °C below average in parts of Wellington, Marlborough, and Canterbury. In contrast, temperatures were above average in Gisborne, Hawke’s Bay, on the South Island West Coast, and in the Southern Lakes district.

Sunshine

Sunshine hours were below normal in many regions, especially in the west of the North Island, from Taranaki to Wellington, and the northern half of the South Island. Sunshine hours were above normal in Southland.

Full report

• Full details of the January 2007 Climate Summary

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.