School holidays weather: Sun, cool temperatures to give way to rain next week

Enjoy the sun while you can, as heavy rain is forecast for the second week of the school holidays due to a strengthening polar jet stream.

Clear skies, a lack of wind and chilly mornings were forecast in the meantime as a high-pressure system lingered over the country.

While the MetService said fine conditions were expected for Auckland from tomorrow into Saturday, a sudden turn was tipped for Sunday and next week.

The change comes amid the National Institute of Water and Atmospheric Research’s prediction for a return to a La Nina climate pattern in late July. Niwa also earlier warned of the potential for a big downpour around the middle of the month - next week.

The fine days for the City of Sails this week were expected to drop to 4C during the nights, with highs of 16C for Wednesday, 15C for Thursday, and 14C for Friday and Saturday, the MetService said.

Despite rain setting in at the end of the good run, temperatures were tipped to be slightly warmer. Sunday could see a few showers, a high of 15C and a low of 6C, and Monday could be dominated by showers all day, a low of 9C and another high of 15C.

In Wellington, Thursday and Friday could be punctuated by showers before fine conditions move in for the weekend. Christchurch, meanwhile, will end its run of sub-zero lows on Friday night - the evenings before will drop to -2C on Wednesday and -1C on Thursday.

MetService meteorologist Ngaire Wotherspoon said the settled weather across New Zealand this week was due to a large area of high pressure, but that could dissipate and let in the moisture next week.

A lack of jet stream action around NZ over the next 10 days...

After frequently being located near the country during autumn, the polar jet has found itself buried deep in the Southern Ocean during winter as a La Niña-like pattern builds.

The jet may strengthen in late July. pic.twitter.com/5ASM6sC6vG

— NIWA Weather (@NiwaWeather) July 8, 2024

“High pressure is caused by air sinking from higher levels of the atmosphere to the surface. While this prevents the formation of most kinds of cloud, pockets of low cloud and fog can get trapped beneath the descending air,” Wotherspoon said.

“Low sun angle at this time of year means it can take a while for low cloud or fog to clear up, especially in shady inland valleys,” she said.

Niwa said the settled weather was also driven by a “lack of jet stream action” but would change as the wind pattern strengthens in late July, with a building La Nina pattern.

Niwa said next week would see increased odds of rainfall and warmer relative temperatures for winter.

Raphael Franks is an Auckland-based reporter who covers breaking news. He joined the Herald as a Te Rito cadet in 2022.