Weather: More chilly mornings to come after Auckland’s coldest weekend of the year

Auckland just had its coldest night in six months, amid cool and dry weather that forecasters say Kiwis are likely to see plenty more of this month.

Temperatures at Auckland Airport plunged to 7.2C early on Sunday morning: that was even cooler than an 8.1C reading the previous morning, and the lowest temperature observed there since last October.

MetService meteorologist Claire O’Connor said it’d been noticeably colder elsewhere across the city over the weekend, with stations at Whenuapai and Ardmore recording lows of 4.9C and 5.6C respectively early on Saturday.

“Auckland hasn’t spent a lot of time in the single digits this year, so to have a couple of nights in a row of cooler temperatures has been noticeable.”

Rather than just the approach of winter, the cooler conditions owed to a ridge of high pressure over the country, with overnight lows in places including Palmerston North and Masterton edging closer to zero.

“Fairly settled conditions and clear skies allows everything to cool down overnight, whereas if you have cloud, that helps to trap the heat in a bit better.”

But it hadn’t been spotless skies everywhere this weekend: cloud has covered much of the South Island, with the lingering high pressure delivering some “anti-cyclonic gloom” to southern centres.

The picture was set to change on Monday, with showers expected over the North Island, along with the south and east of the South Island.

More showery weather was on the cards for the north and east of the North Island on Tuesday and Wednesday – as well as in the south of the South Island – amid cold flows coming from the south.

“We’re expecting more cold mornings this week, which will be from a combination of high pressure lingering around, but also a bit of a southwesterly flow bringing up cooler air,” O’Connor said.

“There may be some heavier showers across the Far North – but we’re not thinking anything significantly heavy.”

Niwa has predicted rounds of chilly, southerly-quarter winds throughout May – and more high pressure – in a parting shot from an El Nino climate pattern expected to fade to neutral conditions as winter begins.

But its latest seasonal outlook picked near-to-above average over the next three months, with a potential trend toward milder conditions in June and July.

With continued bouts of high pressure, there was also little sign of plentiful rainfall to immediately alleviate lingering El Nino-influenced dryness across the east of New Zealand.

Niwa’s just-issued summary for April showed much of the central, eastern and lower North Island, along with Tasman, Canterbury and northern Otago, received below to well-below rainfall last month.

Jamie Morton is a specialist in science and environmental reporting. He joined the Herald in 2011 and writes about everything from conservation and climate change to natural hazards and new technology.