Last year was New Zealand's warmest on record, says Niwa's chief scientist Chris Brandolino.

It surpassed the previous record set in 2021 by 0.2 degrees.

In the annual climate summary of the National Institute of Water and Atmospheric Research released on Wednesday, Brandolino said temperatures were above or well above average for much of the motu.

The average national temperature was up .2 of a degree to 13.7 degrees, with no months recording below average temperatures.

The average national temperature was up more than a degree on the averages for the 30 years to 2010.

The month of November saw the most unusually warm readings and New Plymouth had the most sunshine hours - more than 2600.

Rainfall was also above average for much of the North Island and upper South Island, with the West Coast's Cropp River the wettest, receiving 11 metres of rain.