The first six months of 2016 have been the warmest since records began, but these temperatures may soon seem on the cold side, climate scientist James Renwick says.

"We're going to see more and more of these record warm months and years and in 50 years' time this year's record warm might be normal or even cool. What we think of as warm now is going to be average in a generation or so."

Northerly wind flows had contributed to warmer temperatures and a milder autumn this year, but Dr Renwick said it was the backdrop of climate change combined with weather patterns that created the record temperatures.

His predictions were echoed in climate change projections released by the Ministry for the Environment yesterday, which found average temperatures in New Zealand were expected to rise by up to 1C by 2040 and by up to a further 2C in the 50 years after that.

The report also predicted the number of hot days would increase by 40 to 100 per cent by 2040, while the number of cold nights would decrease by 30 to 50 per cent.
Rainfall would decrease in the north and east of the North Island, but increase elsewhere. The number of dry days each year would increase, as would the intensity of droughts.