The present neutral phase of the El Niño-Southern Oscillation is likely to remain through autumn. An El Niño 'alert' is in place, with some early signs that an El Niño could develop by spring, although this is not yet certain.
South Island temperatures are expected to be above normal in the west and normal to below normal in the east. Near normal temperatures are expected in Nelson and Marlborough. In the North Island, temperatures are likely to be normal or above normal in the southwest and near normal in the north and east.
Near normal rainfall is expected over much of the country. Exceptions are the east of the North Island, where rainfall is likely to be below normal, and the west of the South Island, where normal or above normal rain is expected.
Normal soil moisture levels and river flows are predicted for most parts of the country, apart from the north of the South Island and the east of the North Island, where river flows are expected to be normal to below normal.
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).