Wairarapa's somewhat topsy-turvy summer weather could be settling into a more predictable pattern with above average temperatures likely along with less than normal rainfall and dry soil conditions over the next three months.

Until now the summer weather in most parts of the district has alternated between hot, dry and often humid weather interspersed with regular rain days but February to April could be a different story.

According to NIWA there is a 75 per cent likelihood temperatures will be average or above average for the period, and a good chance rainfall will be down on normal along with low river flows.

In the wider context "international guidance" has shown there is a 96 per cent probability El Nino conditions will continue over the three months before rapidly decaying with a return to normal conditions or a transition to La Nina conditions by the August-October quarter.


On the downside for many is news the "circulation pattern" for the next three months is likely to be often accompanied by westerly winds -- a signature consistent with El Nino.

A breakdown on expectations (assigned in categories above average, near average, and below average) for Gisborne, Hawke's Bay and Wairarapa is:

Temperatures are about equally likely to be above average (40 per cent chance) or average (35 per cent chance).

Rainfall totals and river flows are equally likely to be below normal (40 per cent chance) or near normal (40 per cent chance). Soil moisture levels are about equally likely to be below normal (45 per cent chance) or near normal (40 per cent chance).

NIWA scientists believe El Nino will not return in spring, but that the opposite La Nina pattern is a possibility by late in the year.

The scientists advise the southwest Pacific tropical cyclone season continues through to April.

Ex-tropical weather systems have brought periods of significant rain to the northeast of the North Island from Northland to Bay of Plenty, alleviating incipient dry conditions and further ex-tropical activity cannot be ruled out in the coming three months.

Water temperatures surrounding New Zealand are now close to normal to the west of New Zealand, but cooler than normal to the east.

This pattern, NIWA says, applies not only at the surface but down to about 1000m depth. Ocean models suggest that sea waters will remain cooler than normal to the east of the country for now through to April.

To find out more about normal conditions for this outlook period, refer to NIWA's website, where daily updates on climate maps are available.

The National Climate Centre warns the outlooks published are not weather forecasts and that it is not possible to forecast precise weather conditions three months ahead of time.