Wellington can expect a significant increase in its quota of hot days by the end of the century, a Niwa climate report says.
But that will be balanced by up to 10% more winter rain and more extreme rainfall events.
The annual number of hot days (those over 25degC) in the capital is predicted to rise from the present six to 26 in 2090.
In Wairarapa, the jump is from 24 hot days to 94, heightening the risk of drought.
The climate change report for Wellington region shows specific weather changes for the region for the first time.
The authors say it takes into account inherent uncertainty in climate projections due to likely fluctuations in future greenhouse gas emissions.
Niwa climate scientist Petra Pearce says New Zealand’s climate has warmed about 1degC since 1909.
That has led to more heat waves, fewer frosts, more rain in the south and west, and less rain in the north and east.
“The Wellington region is likely to warm significantly in the future,” Ms Pearce said.
“This has a number of implications and opportunities, including the possibility of growing different crops, an increase in droughts that may limit pasture production and crop growth, and pressure going on water supply.”
The report is the latest in a series commissioned by regional councils.
Other findings for the Wellington region were: Autumn is the season likely to warm the most; annual temperatures will increase by 1degC by 2040 and up to 3degC by 2090; frosts at high elevations of the Tararua Ranges are likely to disappear; spring rainfall will reduce by up to 15% in eastern areas by 2090; up to 15% more winter rainfall along the west coast by 2090. NZN