January 2005

Soil moisture: Severe deficits in Gisborne, Hawke’s Bay, and north Canterbury, significant deficits in many other regions

Rainfall: Below average in many areas, especially eastern Bay of Plenty, above average in the south of the North Island, central Marlborough, and parts of Otago

Temperature: Cool at first, warm later; several heat-waves

Sunshine: Average for most, sunny in the east of the North Island

Relatively cool conditions prevailed during the first ten days of January. However, weather more typical of summer occurred later, the last ten days of the month being very much warmer. Although the January national average temperature of 16.9°C was 0.2°C below normal, it was considerably higher than the December 2004 national average temperature of 13.4°C. Soil moisture deficits became severe in Gisborne, Hawke’s Bay, and north Canterbury, and developed in Northland, Auckland, Bay of Plenty, Taranaki, Wanganui, and Wairarapa. Rainfall was below average in many areas, especially eastern Bay of Plenty. In contrast, rainfall was above average in southern Wairarapa, the Kapiti and Upper Hutt districts, and central Marlborough. Sunshine hours were generally above average in the east of the North Island, as well as north Taranaki, Golden Bay, and West Otago. Anticyclones ('highs') were prevalent over and to the east of New Zealand. Most depressions kept well to the north, west, and southeast of New Zealand.

Highlights

• The highest January 2005 temperatures were 36.2°C recorded at Darfield on the 15th, and 34.4°C recorded in Murchison on the 27th. Both locations experienced extended heat-waves. Darfield maximum temperatures were 30.0°C or higher on 4 consecutive days from the 13th-16th. Murchison maximum temperatures were 30.0°C or higher on 4 consecutive days from the 24th-27th.
• The lowest temperature for the month was -1.0°C, recorded at Wreys Bush (Southland) on both the 9th and 10th, and at Arthurs Pass on the 18th.
• Rainfall totalling 50-100 mm occurred in Kapiti, Horowhenua, Manawatu, and the Hutt Valley on the 5th, with totals exceeding 300 mm in the Tararuas. This caused flash floods on the Kapiti coast. 23 houses near the Waikanae River, which breached its banks, were evacuated, and roads out of Wellington, including SH1 at Paekakariki were closed for a time.
• Of the four main centres Christchurch was both the sunniest and the driest, with near normal temperatures. Auckland was cooler and drier than average, with near average sunshine hours. Wellington was cooler and wetter than average, with near average sunshine hours, and Dunedin was cooler and drier than average with below average sunshine hours.

Rainfall

Rainfall was well below average (less than 25 percent of normal) throughout eastern Bay of Plenty, and less than 50 percent of normal throughout western Bay of Plenty, much of Northland, Auckland, Coromandel, the Kaikoura Coast, and in north Canterbury. It was also drier than average in Waikato, Ruapehu/Tongariro, Taranaki, Wanganui, and Westland. Rainfall was above average in southern Wairarapa, the Kapiti and Upper Hutt areas, as well as central Marlborough.

Temperature

Mean temperatures were at least 0.5°C below average in Northland and Auckland, about 0.5°C above average in Otago and Southland, and near average elsewhere. The national average temperature was 16.9°C, which was 0.2°C below average.

Sunshine

Sunshine hours were generally above average in the east of the North Island, as well as parts of Taranaki, Golden Bay, and West Otago. However, they were near average elsewhere.

Full report

Full details of January 2005 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.