Auckland was the warmest main centre in summer 2024-25. Photo: RNZ / Jordan Dunn
Summer has been a "mixed bag" according to Niwa, with temperature fluctuations in odd months, and unusually dry conditions in typically wet places.
Climate scientist Gregor Macara said while the summer overall was pretty mild, with a nationwide average temperature of 17.3C, there was no shortage of quirks between the months and regions.
"It felt like a mixed-bag. January was actually cooler than normal with 0.8C below average for the nation.
"But for the summer season in total it was 0.5 degrees above average. In terms of ranking our hottest to coldest summers, it was our 21st warmest summer."
He said while that might not sound remarkable, in records dating back to 1909, it was.
"That certainly speaks to the climate change elements, something that's happening insidiously there in the background.
"The temperatures are slowly but surely creeping upwards and stacking the odds in favour of having more of these warmer than normal seasons, or months, or years, rather than cooler than normal."
Macara said another stand out from the summer wrap was just how dry it had been in some area, with three locations - including New Plymouth - that recorded their lowest summer rainfall total on record.
While Taranaki ranked highest in sunshine hours for 2025, with 621 hours, there was a flipside.
"Whilst summer weather is something that a lot of us love and enjoy in our summer break, it's actually creating some pretty challenging conditions for our farmers out there."
He gave a particular nod to farmers in Taranaki, "who have had a very dry summer and are suffering the consequences of it".
Just last week, the Agriculture Minister classified a drought in the area and made $30,000 available to rural support groups.
Oddly, it was the typically wet West Coast that came in as the second sunniest place in the country this year, with 606 hours.
"That's pretty remarkable too. We normally see more westerly winds in New Zealand and those westerlies create cloudier conditions on the west coast of the South Island."
He said the fact that the West Coast was sitting in second position in the sun rankings was likely the result of more easterly winds, and therefore a lovelier summer.
On the temperature highs and lows, Macara said big range between the maximum and minimum was not abnormal, however seeing Kawerau record the highest temperature - 34.8C in December - was a little outside the norm.
"What was really interesting for me, was that the highest temperature for the summer occurred in December.
"Traditionally we think of January and February as our hottest months where we would see our highest temperatures.
"It's relatively unusual. (The highest temperature in December) last happened in the summer of 2015-16, so 10 years ago."
He said the fact that Kawerau was the record holder was also a bit odd, with Canterbury or the east coast of the North Island typically taking out first place.
Further highlights for summer 2024-25:
- The highest temperature was 34.8C, observed at Kawerau on 29 December.
- The lowest temperature was -0.4C, observed at Waipara River North Branch on 25 January.
- The highest 1-day rainfall was 154 mm, recorded at Kokiri (15 km inland from Greymouth, West Coast) on 15 December.
- The highest wind gust was 196 km/h, observed at Cape Turnagain on 5 December.
- The sunniest four locations so far in 2025 are Taranaki (621 hours), West Coast (606 hours), Mackenzie Basin (584 hours), and Central Otago (582 hours).
- Of the six main centres in summer 2024-25, Auckland was the warmest, Hamilton was the driest, Tauranga was the sunniest and wettest, Dunedin was the coolest, and Christchurch was the least sunny.
