Crowds ski at Mt Hutt on brilliant winter's day

Skiers and boarders make the most of excellent conditions on Mt Hutt on Saturday. Photo / Supplied

Skiers flocked to Canterbury's Mt Hutt skifield this weekend as much of New Zealand celebrated fine winter weather.

Most of the South Island was sunny but cold despite rain and northern and eastern parts of the North Island had rain and above-average temperatures.

MetService meteorologist Andy Best said the temperature didn't rise above 2C in Alexandra as low cloud hung in the valleys.

Temperature in the upper half of the North Island were still relatively warm today. The maximum recorded temperature was 18C at Hamilton. However, cold air lingering over the lower South Island and persistent low cloud meant that the lowest max today was just 2C at Alexandra.^AB pic.twitter.com/bm4CcTM637

— MetService (@MetService) June 21, 2020

"But generally the South Island has been pretty good with quite a lot of sunshine due to the easterly/northeasterly flow," he said.

The same northeasterly flow from a complex low-pressure system northeast of the country brought rain to Northland down to Hawke's Bay. The North Island's weather is expected to improve tomorrow, with average maximum temperatures for the time of year in the mid to high teens and slightly warmer-than-usual nights in the low teens.

"Normally they are 8 or 9C at this time of year from Kaitāia to Auckland," he said. "Places like Gisborne and Hastings and Masterton should normally see about 6C overnight, or sometimes 4C, but they are going to stay at 10C."

However another low-pressure system is on its way across the Tasman Sea and is expected to bring more rain on Wednesday from Northland to Coromandel and down the East Coast from Gisborne to Canterbury.

Despite the rain, Auckland's water supply dams are still only 44.83 per cent full compared with the average for this time of year of 78.43 per cent.

But Aucklanders are on track to achieve the June target of using only 410,000 cubic metres a day, with a current rolling seven-day average usage of 409,247 cubic metres.