With winter due to officially begin on Monday, NIWA is forecasting a cold month ahead.
Below average temperatures are likely in many regions.
However NIWA's national climate centre says temperatures for the three months of winter as a whole are likely to be about average.
The exceptions are Canterbury and eastern Otago where average or below average temperatures are expected.
NIWA says more frosts than usual are predicted for the South Island and central North Island.
The institute says rainfall for winter is likely to be normal or above normal for the north and east of the North Island and normal or below normal in the west of the South Island.