Ōtepoti – New Zealand’s summer is forecast to be warmer than usual for many regions, weather forecaster NIWA says.
Summer temperatures are about equally likely to be near average or above average in the east of both islands, very likely to be above average in the north of the North Island and the west of both islands, and most likely to be above average in the north of the South Island.
More sub-tropical northeast winds may result in more frequent hot days, above 25Cdeg, for inland and western parts of both islands. Conversely, a reduction in northwesterly foehn winds will likely mean fewer hot days for eastern areas, such as Christchurch.
Summer rainfall is about equally likely to be near normal or above normal in the north of the North Island and the east of both islands, most likely to be near normal in the west of the North Island and north of the South Island, and most likely to be below normal in the west of the South Island.
Warmer than average regional seas are expected to fuel occasional heavy rainfall events; however, during periods of high pressure, dry spells will occur, particularly about inland and western parts of both islands. A dry spell is possible from mid-December to early January.
The risk for dryness and drought is elevated about the western and lower parts of both islands, especially the South Island, inclusive of Otago, Southland, and the West Coast.
New Zealand’s risk for ex-tropical cyclone activity is normal-to-elevated through April. These systems can cause flooding rainfall, strong winds, and coastal hazards.
Soil moisture levels are about equally likely to be near normal or above normal in the north of the North Island and most likely to be near normal in all other regions.
River flows are equally likely to be near normal or below normal in the west of the South Island, about equally likely to be near normal or above normal in the east of the North Island and north of the South Island, and most likely to be near normal in all other regions.
Temperatures are very likely to be above average in the north of the country. More sub-tropical winds and marine heatwave conditions will result in high heat and humidity at times. There may be similarities with last summer.
Temperatures are very likely to be above average in the Wellington region. More easterly-quarter winds and marine heatwave conditions will result in high heat and humidity at times.
Temperatures are equally likely to be near average or above average along coastal Canterbury and Otago.
Fewer northwesterly winds may lead to fewer hot days above 25˚C, although more frequent onshore winds may contribute to more cloud cover, warmer overnight temperatures, and higher humidity. There may be similarities with last summer.
