Welcome to jandal season: warmest days of the spring so far

Warm nor’westers, or foehn winds, are forecast for parts of the eastern South Island tomorrow and Wednesday, before spreading to the east of the North Island from Wednesday into Thursday.

These toasty winds, tracking from eastern Australia and across the Tasman Sea, will promote the warmest days of the spring so far across New Zealand.

There is a chance that a few spots in the north of Canterbury will approach 30°C on Wednesday and in coastal Hawke’s Bay and Gisborne on Thursday.

While other areas of New Zealand will have above-average temperatures, the 30°C mark will be less likely to be reached. Eastern Southland and Otago will enjoy summery temperatures surging toward 25°C tomorrow, ahead of a southerly change that is forecast to arrive tomorrow night into Wednesday.

Ahead of that southerly change, it is possible that some parts in southern and middle Canterbury may experience record or near-record warm overnight temperatures.

Farther north, Auckland and Hamilton should reach into the 20s on Wednesday and Thursday and Wellington the upper teens. Gusty nor’westers might temper the warmth in Wellington, however.

The last 30°C temperature occurred eight months ago in March – in fact it reached 33.1°C at Hastings, Napier, and Gisborne on March 8. Since then, the warmest temperature observed in New Zealand was at Wairoa, Hawke’s Bay, where it reached 27.1°C on October 20.

Last year, we didn’t need to wait until November to surpass the 30°C threshold as Kaikoura, Canterbury reached 31.8°C on October 7.

As warmth unfolds on the east side of the South Island, drenching rains may cause flooding along the West Coast from tomorrow into Wednesday.

A weak southerly is forecast to move up the eastern South Island late on Wednesday, putting an end to the summery warmth. The east of the North Island may have one more day of unseasonably warm weather on Friday before cooler air arrives in time for the weekend.

Another round of warm temperatures, especially in the east, is possible early next week.