New Zealand has just come through its warmest June since national records began in 1909, with a nationwide average temperature of 10.6°C that has climate scientists pointing to a run of warm months with few modern parallels.
The figure comes from the Monthly Climate Summary published by Earth Sciences New Zealand, the research body that carries out the long-term climate monitoring work many New Zealanders still associate with NIWA. According to the summary, June sat well above the long-term average across much of the country, and in a large number of places the readings came in more than 2°C warmer than a typical June.
The single highest temperature of the month was 26.0°C, recorded at Bromley in Christchurch on 20 June, a reading that would not look out of place in late spring let alone the middle of winter. Even more striking was what happened in the capital. Wellington’s Kelburn station logged its highest-ever June temperature not in the afternoon sun but in the small hours, somewhere between 2am and 4am.
Earth Sciences New Zealand climate scientist Gregor Macara said that overnight reading was the detail that stood out to him. “It was overnight, it was dark, there was no sunlight and yet that was when it observed its highest ever June temperature,” he said. Warm nights, rather than scorching days, were a feature of the month in several parts of the country.
Across the six main centres the pattern was mild almost everywhere. Auckland and Tauranga were the warmest, finishing level with one another, while Christchurch was the coolest of the group. Tauranga was also the sunniest of the main centres. Wellington had the least flattering month of the six, coming out as both the wettest and the least sunny, while Dunedin was the driest.
The warmth also showed up in the running sunshine tallies for the year so far. Nelson was leading the country on 1,410 hours of sunshine, followed by New Plymouth on 1,386 hours, Whakatāne on 1,356 hours and Richmond on 1,334 hours. Those totals help explain why the top of the South Island and the western Bay of Plenty have felt so settled through the first half of the year.
Macara said the June result was not a one-off oddity but part of a longer pattern that has become hard to ignore. Looking back over more than a decade of monthly summaries, he said the balance had tipped firmly towards heat. “By far and away we’re setting far more high temperature records or near records both nationwide but also at individual locations throughout the country,” he said.
Earth Sciences New Zealand pointed to conditions in the Pacific as part of the reason for the mild month. By the end of June an El Niño pattern had become established in the tropical Pacific, and sea surface temperatures around New Zealand were mostly above average. Warmer water around the coast tends to keep overnight temperatures up, which fits with the unusual after-dark records seen during the month.
That El Niño backdrop has already been formally declared by forecasters, who have warned it could develop into one of the strongest such events on record as the country moves towards spring and summer. El Niño often brings drier conditions to the north and east of the country and wetter weather to parts of the west and south of the South Island, though the exact effects vary from event to event.
A single warm month does not tell anyone much on its own, and New Zealand has had mild Junes before without them signalling anything in particular. What the scientists are watching is the frequency of these records. When high-temperature marks keep falling year after year, at both the national level and at individual weather stations, that steady drumbeat carries more weight than any one month.
For most households the practical side of a warm June was simply a gentler start to winter. Fewer hard frosts, lower heating bills in some regions and gardens that kept ticking along later than usual are the kind of everyday effects that come with a mild month. Ski field operators, on the other hand, tend to watch these summaries more nervously, since warm air and warm seas are not what they want to see as the season gets under way.
The mildness has not meant calm weather everywhere. Forecasters have flagged a significant rain event moving onto the eastern side of both islands, with warnings issued for the headwaters of Canterbury lakes and rivers south of Arthur’s Pass. Warm, moisture-laden air of the kind that has kept temperatures up can also carry a great deal of rain, and the coming days are expected to test that in parts of the country.
Earth Sciences New Zealand will publish its next monthly summary in early August, which will show whether July has continued the warm run or brought conditions back closer to what most people would recognise as a proper New Zealand winter.
What was June like where you are? Did it feel unusually mild, and have you noticed the warmer nights that the scientists are talking about? Share your thoughts in the comments below.
This article was written by AI, briefed to report the facts, hopefully without some of the bias people bring to the job 🙂
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