Climate Summary for May 2010

Eastern areas extremely wet!

  • Rainfall: Extremely wet in eastern regions of both islands, with several floods.  Well below normal rainfall for the West Coast, Fiordland and Southland.
  • Soil moistures: Now at capacity across most regions; still drier than normal in Waikato and Manawatu.
  • Temperature:  Above average in the Wairarapa, Nelson, Westland, Fiordland and around Christchurch.  Generally near average elsewhere.
  • Sunshine: Extremely cloudy for Nelson, Marlborough, coastal mid-Canterbury, Wellington, Wairarapa.  Rather sunny for Westland, Fiordland, Southland, central North Island and Auckland. 

May was a stormy month overall, with more lows than normal located in the Tasman Sea, and higher pressures east of the Chatham Islands.  This produced more northeasterly winds than normal over New Zealand, resulting in an extremely wet month and several flood events in eastern regions. Soil moisture levels are now at capacity in most regions, but soils remain drier than normal in Waikato and Manawatu. 

It was an extremely wet May in eastern regions of both Islands. Rainfalls were more than 200 percent (double) normal in Nelson, Marlborough, Canterbury and eastern Otago, Coromandel, Bay of Plenty, Hawkes Bay and coastal Wairarapa.  Rainfall was also well above normal (more than 150 percent of normal) in eastern Northland and Auckland, and above normal (between 120 and 150 percent of normal) in Taranaki and Gisborne. In contrast, it was very dry on the West Coast, and in Fiordland and Southland, with less than 50 percent of normal rainfall recorded. 

May temperatures were above average (between 0.5°C and 1.2°C above average) in Wairarapa, Nelson, Westland and Fiordland (showing the effects of the enhanced northeasterly winds), and around Christchurch.  Temperatures were mostly near average elsewhere (within 0.5°C of the long-term average), except for small pockets of below average temperatures (between 0.5°C and 1.2°C below average) in eastern Otago.  The New Zealand national average temperature was 11.3°C (+0.6°C above the 1971-2000 May average).

It was an extremely cloudy May for Nelson, Marlborough, coastal mid-Canterbury, Wellington and the Wairarapa.  Sunshine totals were also below normal (between 75 and 90 percent of normal) in other parts of Canterbury, Taranaki, Bay of Plenty and Gisborne.  In contrast, sunshine totals were above normal (between 110 and 125 percent of normal) for Westland, Fiordland, Southland, central North Island and Auckland.

Further Highlights

  • The highest temperature was 25.1°C, recorded at Motueka on the 13th (a new May record there).
  • The lowest temperature was -5.2 °C, recorded at Windsor on the 6th (not a record).
  • The highest 1-day rainfall was 153 mm, recorded at Whakatane Airport on the 24th (a new May record there).
  • The highest wind gust was 146.4 km/hr, recorded at Puysegur Point on the 7th (the 3rd-equal highest gust for May at this site).
  • Of the six main centres, Auckland and Tauranga were equally the warmest; Tauranga was the wettest but sunniest, Christchurch the coolest, and Hamilton the driest.

Full report

Full details of the  May 2010 Climate Summary

Climate statistics table

Climate statistics for PDF File May 2010

For further information, please contact:

Ms Georgina Griffiths – Climate Scientist– NIWA National Climate Centre, Auckland, Tel. (09) 375 4506 (work) or (027) 2936545 (mobile); or

Dr Andrew Tait – Climate Scientist – NIWA National Climate Centre, Wellington, Tel.  (04) 386 0562 (work) or (027) 327 7948 (mobile)