Climate Summary for May 2008

May 2008: Cold; Record dry and calm in the west and over much of the South Island; Wet in the east of the North Island

• Temperature: Cold overall; Very cold in inland areas of both islands especially at night;
• Rainfall: Record low rainfall in Kapiti, Nelson and Marlborough and the Tekapo basin; double average in Gisborne and Hawke’s Bay;
• Sunshine: Very sunny in the west of both islands; below average in Gisborne and Hawke’s Bay

May was a cold month, with the national average temperature of 9.6°C being 1.1°C below average. This made it almost 4°C lower than mean air temperatures in April, and the coldest May since 1992. Mean temperatures were particularly cold in inland South Island areas being 1.5 to 2°C below average, and also in central North Island areas. It was particularly cold at night in central and south western areas of the North Island, and inland South Island areas, with daily average minimum temperatures at least 2°C below average. It was especially sunny in western areas with record totals recorded in the Waikato and Manawatu. In contrast it was very cloudy in the east of the North Island. It was much frostier than normal, with ground frosts of 5°C or more occurring on 24 days in some inland areas.

Manawatu/Horowhenua, and the north, western and alpine areas of the South Island endured extreme low rainfall. Totals were a mere tenth (10 percent) of normal in Kapiti, Nelson and central Marlborough, Tekapo and Timaru, with monthly totals of less than 10 mm making it the driest May on record in these places. May totals were less than half (50 percent) of normal throughout other western and alpine areas and the Manawatu. By contrast, rainfall was double normal (200 percent) in the east of the North Island.

In terms of other extremes it was a very quiet month, with few high intensity rainfall events. Winds were also much lighter than normal in many areas. Anticyclones dominated the weather patterns, and were much more frequent than normal to the south and southeast of the South Island. These blocked the progression of lows, which were much more frequent to the north east of the North Island. Between these features, more easterly winds than normal occurred over the North Island, with much lighter winds than normal over the South Island. There were about 5 days less of strong winds than normal in many areas.

Further Highlights

• The highest temperature during April 2008 was 21.5°C recorded at Cheviot on the 8^th. The lowest air temperature during the month was -7.7ºC recorded at Albert Burn in Central Otago on the 4^th.
• The highest 1-day rainfall was 84 mm recorded in Khyber Pass Road, Auckland on the 4^th.
• The highest wind gust for the month was 183 km/h at Mokohinau Island on the 11^th, in strong easterly conditions.
• Of the five main centres, Auckland was the warmest and the wettest. Hamilton was by far the sunniest, and Christchurch the driest and coldest.

Rainfall

Rainfall was only one tenth (10 percent) of normal in Kapiti, Nelson/Marlborough and only half (50 percent) of normal throughout other western areas and alpine South Island areas. Double (200 percent) of normal rainfall occurred in the east of the North Island.

Temperature

Mean temperatures were between 1.5 and 2°C below average in inland areas of both islands, and 1°C below average in most other areas. Night time minimum temperatures were especially low in the west of the North Island, and inland South Island areas.

Sunshine

Above average sunshine hours (at least 110 percent of normal) occurred in the west of both islands and inland areas of the South Island. Sunshine totals were well below normal in the east of the North Island.

Full report

• Full details of the May 2008 Climate Summary

Climate statistics tables

Climate statistics May 2008

For further information, please contact:

Dr Jim Salinger – Principal Scientist, Climate NIWA National Climate Centre – Auckland Phone +64 9 375 2053 [email protected]

Dr Jim Renwick – Science Leader NIWA National Climate Centre – Wellington Phone +64 4 386 0343 [email protected]

 

Acknowledgement of NIWA as the source is required.