Temperatures of up to 39°C indicate a scorching summer forecast
The warning comes from Ben Knoll, a meteorologist at the National Institute of Water and Atmospheric Research (NIWA), who says El Niño conditions will quickly change weather patterns in the coming weeks and months.
He says the first records could fall as early as late September.
“As we look at the last 10 days of the month, we will see air masses coming across the Tasman from the deserts of Australia,” Noll says.
“When those air masses reach New Zealand and the air parcels from the Southern Alps descend into the Canterbury region, as well as Otago, Marlborough, Hawke’s Bay, Gisborne and the Wairarapa, they warm up and dry out.”
This hot, dry air has the potential to dramatically influence the weather we experience on Earth.
“We could see temperatures of up to 25C, and possibly even higher, during the last week of September. Looking back, New Zealand’s national temperature record for September was 28C.
“If we get that in the last week of the month, it will put us up there with the warmest September days New Zealand has ever seen.”
This will mark the beginning of what could be a very different summer from the last the country has experienced.
“The last two summers, temperatures have been below 35 degrees Celsius, but I think that streak will end,” Noll says.
“This summer, we could reach 36, 37, 38 or maybe even 39 degrees Celsius later in 2023 and early 2024 when these hot, dry air masses cross the Tasman Sea from Australia.”
However, those who rejoice at the prospect of a hot, dry summer may want to put the cork back in their Champagne.
The potential for these conditions to occur will present a range of risks not seen in Aotearoa for some years.
“The El Niño we have built is among the strongest we have seen in more than 80 years,” Noll says.
New Zealand previously experienced strong El Niño conditions in 2015-16, 1997-8, 1982-3 and 1972-3 – and the consequences were felt across the country.
“New Zealand has had very bad and expensive droughts in some of those years,” Noll says.
“From an agricultural perspective, even though it has been very wet and your pastures may remain wet, the combination of drier weather and wind can cause soil moisture levels to dry out very quickly.”