| Temperature | Temperatures were above average (0.51-1.20°C above average) or well above average (>1.20°C above average) for most of the country. Temperatures were near average (±0.50 of average) for Christchurch, inland Wairarapa, Kāpiti Coast, parts of Manawatū and Hawke’s Bay, the Central Plateau, and parts of Waikato. |
| Rainfall | Rainfall was below normal (50-79% of normal) or well below normal (<50% of normal) for southern, central, and eastern parts of Southland and Otago, much of Canterbury, parts of the West Coast, northern Wairarapa, Manawatū, Whanganui, much of Hawke’s Bay and Gisborne, northern Waikato, and northeastern Northland. Rainfall was above normal (120-149% of normal) or well above normal (>149% of normal) for western Southland, Marlborough, Nelson, southern parts of the Greater Wellington region, the Central Plateau, and inland and western Bay of Plenty. Rainfall was near normal (80-119% of normal) elsewhere. |
| Soil Moisture | At the end of May, soils were drier than normal for Whanganui, Manawatū, southern and central Hawke’s Bay, Dunedin, and southern Otago. Soils were wetter than normal about eastern Canterbury, and Marlborough. Soil moisture levels were generally near normal elsewhere. |
Overview
May 2025 mean sea level air pressure (MSLP) was higher than normal over and surrounding Aotearoa New Zealand, and lower than normal well to the south of the country. This resulted in more westerly airflows than usual over the southern South Island. The prevalence of high MSLPs and marine heatwave conditions surrounding most of New Zealand contributed to extended periods of warm weather. May temperatures were above average (0.51-1.20°C above average) or well above average (>1.20°C above average) for most of the country. It was an especially warm month for inland and southern parts of the South Island, where May temperatures were typically at least 1.5°C higher than average. The nationwide average temperature in May 2025 was 11.9°C. This was 0.8°C above the 1991-2020 May average from NIWA’s seven station temperature series which begins in 1909, making it New Zealand’s 10th-warmest May on record.
Rainfall was below normal (50-79% of normal) or well below normal (<50% of normal) for southern, central, and eastern parts of Southland and Otago, much of Canterbury, parts of the West Coast, northern Wairarapa, Manawatū, Whanganui, much of Hawke’s Bay and Gisborne, northern Waikato, and northeastern Northland. The lack of rainfall was accompanied by clear skies for parts of the country, resulting in relatively high sunshine hours for the time of year. Notably, Lake Tekapo observed its sunniest May since records began in 1928. Auckland, Cheviot, Rangiora, and Cromwell observed their second-highest total sunshine hours for May, respectively.
Further highlights
- The highest temperature was 24.2°C, observed at Gisborne on 1 May and Christchurch on 17 May.
- The lowest temperature was -5.0°C, observed at Manapouri on 19 May and Tūrangi on 22 May.
- The highest 1-day rainfall was 183 mm, recorded at Milford Sound on 8 May.
- The highest wind gust was 200 km/h, observed at Cape Turnagain on 30 May.
- Of the six main centres in May 2025, Auckland was the warmest, Tauranga was the sunniest and wettest, Dunedin was the driest and least sunny, and Christchurch was the coolest.
- The sunniest four locations in 2025 so far are Taranaki (1257 hours), Bay of Plenty (1196 hours), Auckland (1182 hours) and Mackenzie Basin (1158 hours).
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