A mild winter is expected, with above average temperatures in all districts except the east of the South Island, where above average or average temperatures are expected. Despite this, some typical winter cold spells are likely, with frosty conditions in inland places. Local sea surface temperatures are likely to remain above average and local circulation patterns are expected to favour enhanced northerly or northwesterly wind flow.
Normal or below normal rainfall is expected in the east of the North Island and in parts of Southland and inland Otago, with near normal rainfall likely elsewhere.
Soil moisture levels are predicted to be normal in most regions. River flows are predicted to be normal everywhere, except for normal or below normal flows in eastern regions of both islands.
The tropical Pacific is moving towards a moderate La Niña, which is likely to last through the winter. Conditions are changing rapidly at present, and there is not yet a clear consensus for spring and summer.
A. Climate models give no strong signals about how the climate will evolve, so we assume that there is an equal chance (33%) of the climate occurring in the range of the upper, middle or lower third (tercile) of all previously observed conditions.
B. There is a relatively strong indication by the models (60% chance of occurrence) that conditions will be below average, but, given the variable nature of climate, the chance of average or above-average conditions is also shown (30% and 10% respectively).