“To get fifth place is pretty notable and that was despite the fact there was a relatively cold August so that showed just how warm June and July were,” Macara said.
These conditions were tied to the warm sea temperatures around the country and the lingering effects of the decaying La Nina at the start of the season, which usually gives the country more northeasterly, subtropical winds.
For Whanganui, wind coming from the east is usually both warmer and drier than from the west as it has to pass over more land and mountain ranges to get to the region.
“Usually that process, as it passes over land, allows the air to both dry out, it tends to drop its precipitation over those mountain ranges and then dries as it moves out, and once it dries out it warms as it passes over land.”
The now developing El Nino usually results in more southwesterly winds which would be a factor in the cool August for the region.
Whanganui also had a dry winter, with 165mm of rain falling at Spriggens Park, only 63 per cent of normal.
“Basically you got 100mm less than what you’d normally get over winter,” Macara said.
Rainfall across most of the country was below normal and there was a considerable reduction in the number of rain-bearing storms arriving from the north compared to earlier in the year.
“Much of the North Island has been a lot wetter than usual over the past year or two, it’s interesting to see that shift has happened,” Macara said.
However, in August Whanganui had rainfall levels around normal, with 90mm of rain falling at Spriggens Park, 7 per cent more than normal.
Moving into spring, rainfall was expected to stay below normal across the season and temperatures were also expected to stay around average, with a prevailing area of high pressure.
“In other words, high pressure means we generally see clearer skies and settled weather,” he said.
The clearer skies meant it was likely nights and mornings would be cooler than usual.
Drier soils may also play a part in this, as drier, harder soils retain less heat overnight.
“It may not necessarily be the case that daytime temperatures [are] cooler than normal, they might be about normal or even above, but because those night time temperatures are expected to be a bit cooler ... that brings down the overall average.”
There was also an expectation for higher-than-normal wind speeds in the region, which was also likely a consequence of the growing El Nino.
Finn Williams is a multimedia journalist for the Whanganui Chronicle. He joined the Chronicle in early 2022 and regularly covers stories about business, events and emergencies. He also enjoys writing opinion columns on whatever interests him.
