A Muggy and Wet Week Ahead – Humidity Returns with a Vengeance!

This week, Aotearoa New Zealand is set to experience a warm and moist weather pattern as a swath of tropical air blankets the country. The North Island is already feeling the effects, with persistent rain from a low-pressure system moving in from the north. The Coromandel Peninsula to the Kaimai Range, as well as Gisborne/Tairāwhiti north of Tolaga Bay, are under Orange Heavy Rain Warnings until 8pm and 9pm tonight (Monday), respectively.

MetService Meteorologist Katie Hillyer notes, “Over the past 24 hours, the Pinnacles on the Coromandel Peninsula has recorded 200mm of rainfall. Even for this mountainous station, that’s an impressive amount.” Additional rainfall of 70-90mm is expected in these areas today.
High humidity will also dominate the North Island this week. “The combination of warm, humid air and extensive cloud cover acts like an insulating blanket, leading to warmer nights and potentially uncomfortable sleeping conditions,” explains Hillyer. Rotorua exemplifies this trend, with just a 2°C difference between yesterday’s maximum temperature and this morning’s minimum. Whanganui and Hawkes Bay are also in the spotlight, with temperatures expected to soar above 30°C in the coming days—a stark contrast to the cooler summer experienced in the east so far.

Overnight, the focus will shift from the northeastern North Island to the South Island, as rain associated with a low-pressure system from the Tasman Sea moves in. The Tasman District Ranges have been upgraded to an Orange Heavy Rain Warning, with 80-100mm of rain expected between 9pm tonight and 7am tomorrow. A Heavy Rain Watch is also in place for the Richmond and Bryant Ranges. By tomorrow morning, rain will spread to the eastern parts of the South Island, bringing much-needed moisture to some parched areas.

Hillyer also warns of potential thunderstorms: “On Tuesday afternoon and evening, Canterbury down to Southland, as well as Westland through to Buller, could see thunderstorms develop.” Rain will continue to affect much of the country through Thursday, with today and Tuesday being the most intense days.

“Cloudy and wet conditions will dominate most of the country until Thursday and into Friday,” says Hillyer. “A ridge of high pressure will then begin to push out the humidity, bringing fresher air and a welcome change to the muggy weather.”