Science Centres: Climate

Climate summary: the 2007 year

Rainfall anomaly for 1 January to 31 December 2007

Average air temperature anomaly for 1 January to 31 December 2007

While drier than average in many places, New Zealand’s climate year was punctuated by some spectacular weather events.

Generally drier than normal conditions were punctuated by unusually low rainfall in some locations. Record low annual rainfalls were recorded at East Taratahi (Wairarapa) and Tara Hills (north Otago), with less than 70% of normal, and NewPlymouth Airport, Palmerston North Airport, Stratford, and Okarito with less than 80% of normal.

Parts of the south and east of the country, and Bay of Plenty and Wellington, recorded unusually sunny years.

The national average temperature for 2007 of 12.7 °C was close to normal. The largest positive temperature anomaly occurred in May at 1.7 °C above normal. The largest negative temperature anomaly occurred in the next month, June, with a national temperature of 0.6 °C below  normal.

Other notable climate features in various parts of the country were the disastrous floods in Northland, with contrasting very dry conditions and drought in the east of the North Island. There was an unprecedented swarm of tornadoes in Taranaki, destructive windstorms in Northland and in eastern New Zealand in October, and several spells of hot weather. Extreme weather included two severe hailstorms and seven damaging electrical storms.

The year saw a swing from El Niño to La Niña climate phases of the El Niño–Southern Oscillation. The start of the year was dominated by a weakening El Niño in the equatorial Pacific. From September onwards La Niña conditions developed in the tropical Pacific, with a noticeable increase in the frequency and strength of the westerlies over New Zealand in October and then a significant drop in windiness from November. Moderate to strong La Niña conditions developed by the endof the year. Overall, more anticyclonic conditions than usual occurred over New Zealand.

A full climate summary of the climate for 2007 is available at
www.niwascience.co.nz/ncc/cs/annual/aclimsum_07