If you are enjoying a wonderfully warm Wairarapa autumn then prepare yourself for the good news - the mild weather looks set to continue right through to the end of July.

That is according to Niwa, which is picking there is a 75 per cent chance temperatures in Gisborne, Hawke's Bay and Wairarapa will score above average beyond mid-winter.

At the same time, rainfall totals are expected to be about normal for the time of year and soil moisture levels and river flows are likely to be below the normal range.

That friendly weather pattern - although farmers and wood merchants may not regard it as such - will not be unique to the lower North Island but is expected to persist in all regions, although in the far north of the North Island more rain than normal could fall.


The predictions come with a word of caution, though, with people reminded June and July are winter months "and frosts will occur from time to time in cooler locations".

Sea surface temperatures are forecast to be above normal over the entire three-month period, especially to the west of New Zealand.

In an overview of the weather situation, Niwa scientists revealed El Nino conditions in the tropical Pacific weakened further this month with sea surface temperatures now only about 1C warmer than usual.

Moreover, cooler than normal sub-surface waters have spread eastward from the western Pacific, and temperatures are more than 3C below normal between 50-100m depth east of 160 degrees west.

Scientists say these changes in sub-surface temperatures mean the tropical Pacific is poised to make a rapid transition into La Nina conditions.

The seas surrounding New Zealand are exceptionally warm for this time of year, and models suggest they will remain warmer than normal from May to July.

The Niwa scientists say given the higher moisture source from the warmer surface waters, together with more troughs and low-pressure systems that typically enter the Tasman Sea in the winter season, it is possible that New Zealand will experience more severe storms than usual this winter.