The North Island's sun-starved summer will be followed by a wetter-than-normal autumn dominated by overcast days.

The National Institute of Water and Atmospheric Research said cool sea temperatures and a stormy Tasman Sea would produce more rainfall in the northern North Island and slightly cooler temperatures in eastern areas between March and May.

Climate scientist Georgina Griffiths said the mild La Nina climate cycle was expected to disappear by Easter, which meant sea temperatures and Tasman conditions would be the main influence on New Zealand's next three months of weather.

"The Autumn forecast isn't particularly stunning. The seas are about half a degree cooler than what they should be for this time of year and more lows in the Tasman Sea is never good news for New Zealand."


She said the combination of cooler coastal temperatures and winds from the Tasman would produce mostly cloudy days.

Air temperatures are expected to be near-normal or below-normal for the eastern sides of both islands, and normal elsewhere. Auckland is usually around 18.5C in March, 16.2C in April, and 13.7C in May.

All regions north of Taupo could expect more rain than normal, but Dr Griffiths said deluges were unlikely.

"This summer we've had a lot of deluge rainfall, but Autumn isn't normally characterised by that - it's just an unsettled outlook."

The first day of March brings to an end a mostly miserable summer for the North Island. But Dr Griffiths pointed out that it was not a gloomy season for everyone.

Most regions south of Nelson experienced dry, warm conditions. The usually drenched Milford Sound had its driest summer in a 90-year temperature record, and Invercargill and Mount Cook regions also had parched summers.

Takaka and Nelson, on the other hand, had their wettest summers on record, with Takaka recording an incredible 1295mm of rainfall - three times the usual.

The cloudier-than-normal conditions meant the highest recorded temperature was 31.7C at Lake Pukaki (near Mount Cook) on 4 January.

This was 10 degrees lower than last summer's record in Timaru.


Near-normal or above-normal rainfall in Northland, Auckland, Waikato, Coromandel, Bay of Plenty, Taupo, Taranaki, Gisborne and Hawkes Bay, and Nelson.

Expected rainfall
* Whangarei: 380-460 mm
* Auckland: 270-320 mm
* Hamilton: 290-340 mm
* New Plymouth: Around 370 mm
* Tauranga: 340-410 mm
* Gisborne: 270-320 mm
* Wellington: Around 310 mm
* Nelson: 240-290 mm
* Christchurch: Around 160 mm
* Dunedin: Around 210 mm


Average or below average in eastern areas of both Islands, and near average elsewhere.

Summer records
* Driest summer on record in Milford Sound
* Second driest summer on record in Mt Cook
* Wettest summer on record in Takaka and Nelson
* Highest temperature reading: 31.7C, Lake Pukaki, Jan 4.