Aucklanders are being advised to hit the cold button on heat pumps as stifling hot and humid weather continues over the next couple of days.
MetService forecaster Gerard Bellam said a warm, humid air mass crossing the North Island will continue to bring overnight temperatures in the low 20s and continue into Monday morning.
"I know people in Auckland don't like this humid weather, it's uncomfortable. Today will be cloudy with a few showers around that clammy sort of air.
"It will be stifling at night-time, sleeping and stuff, and people will really value those heat pumps and turn them on to cool," he said.
Several North Island cities, including Whanganui, Napier and Masterton, are expected to have daytime temperatures in the high 20s from a northerly flow. Auckland is in for 23C with patches of rain.
In the South Island, the mercury in Christchurch yesterday hit 30C, about 9C higher than normal for this time of the year.
Bellam said Christchurch and Kaikōura will be in the high 20s today before the temperatures "drop off the cliff" to the low teens in places like Timaru and Ashburton on Monday.
Heavy rain warnings were issued last night for Westland, the West Coast and the top of the South Island.
Bellam said there is a moderate risk of thunderstorms in Dunedin, up through North Otago to Oamaru and Canterbury this afternoon.