Warm and wet for the South Island
| Temperature | Temperatures were well above average (>1.20°C above average) or above average (0.51-1.20°C above average) for the majority of the South Island, Taranaki, most of Manawatū-Whanganui, the central North Island, western Bay of Plenty, and parts of Hawke’s Bay. Temperatures were below average (0.51-1.20°C below average) for Whangārei. Near normal temperatures (±0.50°C) were recorded elsewhere. |
| Rainfall | Rainfall was below normal (50-79% of normal) or well below normal (<50% of normal) for parts of Northland, parts of the Waikato, Taranaki, Manawatū-Whanganui, Bay of Plenty, Wellington, and Hawke’s Bay, Nelson, most of Marlborough, and much of the Canterbury low country including Banks Peninsula. Rainfall was above normal (120-149% of normal) or well above normal (>149% of normal) for a majority of Southland, Otago, and Westland. Elsewhere, near normal rainfall (80-119% of normal) fell in August. |
| Soil Moisture | At the end of winter, soil moisture levels were higher than normal for coastal parts of Otago and Kaikōura. Near normal soil moisture levels were typical for the remainder of the country. |
Overview
August started off cold with southerly winds bringing some of the coldest air of the winter to Aotearoa New Zealand. These were followed by the development of high pressure centres, which were mainly anchored over the Tasman Sea west of the North Island. Aside from a few interruptions by fronts or low pressure, high pressure was the dominant pattern through the third week of the month. By the end of August, westerly quarter flows dominated, with highly variable weather. Overall, mean sea level pressure was higher than normal for the entire country, and highest over the North Island. The result was wetter than normal conditions for a portion of the South Island, mainly the west and south. Meanwhile, very dry conditions were felt for much of the North Island. August was also quite warm in the South Island, with above average temperatures for nearly all of the South Island and parts of the interior North Island, and closer to normal temperatures in the remainder of the North Island. El Niño conditions continued to strengthen through the month of August. Sea surface temperatures (SSTs) surrounding New Zealand were mostly above average, with the exception of the east coast of the North Island. At the end of August, Marine Heatwave (MHW) conditions[1] were present around much of the South Island, and around the North Island primarily along the east and north of the Northland region.
The nationwide average temperature in August 2026 was 9.7°C. This is 0.7°C above the 1991-2020 August average, making it New Zealand’s equal-13th warmest August since Earth Sciences New Zealand’s seven station temperature series began in 1909. The month started with cold outbreaks and led to several cold minimum temperature records from 6 to 8 August. Otherwise, August was warm overall for the South Island and across portions of the lower and central North Island.
August 2026 was dry for much of the North Island and very wet for the west and south of the South Island. The driest locations were generally in the Waikato, Manawatū-Whanganui, Taranaki, and in the Wellington region. As the month progressed, strong westerly quarter flows led to periods of heavy rain, with highest rainfall anomalies in Fiordland, Westland, Otago, and Southland. Rainfall was below normal (50-79% of normal) or well below normal (<50% of normal) for western Northland, the west and south of Auckland, majority of the Waikato, Taranaki, Manawatū-Whanganui, inland and eastern Bay of Plenty, Wellington and most of the Wairarapa, and Hawke’s Bay, Nelson, eastern Tasman, most of Marlborough, and much of the Canterbury low country including Banks Peninsula. Rainfall was above normal (120-149% of normal) or well above normal (>149% of normal) for a majority of Southland, Otago, Westland, and portions of the northern Canterbury high country. Elsewhere, near normal rainfall (80-119% of normal) fell in August.
Further Highlights:
- The highest temperature was 23.5°C, observed in Timaru on 25 August.
- The lowest temperature was -10.7°C, observed at Cass (inland Canterbury) on 6 August.
- The highest 1-day rainfall was 194 mm, recorded at Franz Josef on 26 August.
- The highest wind gust was 207 km/h, observed at Cape Turnagain on 23 August.
- Of the six main centres, Auckland was the warmest, Tauranga was sunniest and the wettest, Wellington was the least sunny, Christchurch was the coldest and the driest.
- The sunniest four regions in 2026 so far are Nelson (1823 hours), Whakatāne (1793 hours), New Plymouth (1760 hours) and Richmond (1722 hours).
[1] Defined as five or more consecutive days with SSTs above the 90th percentile for the time of year.
