New Zealand Faces Warm, Dry Summer with Rainy End in North

New Zealand is set to experience a warm and predominantly dry summer, with significant dryness expected across most regions. However, the northern North Island is likely to see a rainy conclusion to the season. According to the summer outlook from Earth Sciences New Zealand, presented by principal scientist Chris Brandolino, above-average temperatures are forecasted for the western and upper North Island, as well as the upper South Island.

Brandolino expressed concerns about the widespread dryness impacting the country. He characterized the upcoming months as a “summer of two personalities,” with the upper North Island exhibiting a contrasting weather pattern. While the overall trend points towards heat and aridity, this region anticipates increased rainfall in late summer.

The outlook indicates a 65% likelihood of above-average temperatures for areas including Waikato, Bay of Plenty, Auckland, Northland, and Coromandel. The western and upper North Island, alongside the upper South Island, have slightly lower probabilities of warmer weather, estimated at 55%.

Brandolino highlighted the “significant to severe marine heatwave conditions” currently affecting New Zealand’s coastal waters. These warm ocean temperatures are contributing to elevated air temperatures and increased humidity. He noted, “If our ocean temperatures are running warmer than average, then our air temperatures are very likely going to be warmer than average.” This phenomenon is expected to be particularly noticeable in the North Island, where coastal waters are reported to be three to four degrees Celsius above normal, hovering around 20°C.

As humidity rises due to warmer oceans, the potential for heavy rainfall correspondingly increases. Brandolino stated, “That does load the dice for big rain events. Something like this is more likely to occur in the second half of summer.” Consequently, the upper North Island is projected to receive normal or above-normal rainfall especially in the latter part of the season.

For the rest of the country, temperatures are expected to remain average or exceed average levels. The South Island may experience cooler temperatures in December, which could counteract the overall trend of warmth. Despite some days already reaching or surpassing 30°C, these cooler snaps may prevent the season from being categorized as entirely above average.

Earth Sciences New Zealand has also issued warnings about the potential for extended dry spells this summer. Brandolino noted that the dryness experienced last summer in the western and lower North Island continues to be a concern, with the South Island also at risk. He stated, “What there is is a pretty overwhelming theme for much of the country for dryness.”

While some rain is anticipated in the short term, Brandolino cautioned that it is unlikely to set the tone for the entire season. As New Zealand progresses into summer, the contrasting weather patterns will likely shape the experiences of its residents, particularly in the northern regions.