New Zealand’s equal-2nd warmest year on record. Annual temperatures were above average across the majority of New Zealand, including much of the North Island as well as the western and southern South Island. See complete 2018 Annual Climate Summary details.
Air pressure is forecast to be higher than normal to the southeast and lower than normal to the north of New Zealand. This is expected to be associated with developing La Niña-like northeasterly air flow anomalies, although a westerly flow anomaly, which may be strong at times, is favoured to continue for much of October.
September – November 2020 air pressure is forecast to be higher than normal to the east and lower than normal to the northwest of New Zealand. This is expected to be associated with La Niña-like northeasterly air flow anomalies.
NIWA’s South Island snow and ice monitoring stations have confirmed what many skiers have been talking about: winter has been dry and snow coverage has been poor. In fact, several sites have recorded half their typical snow depth for this time of year.
During periods of northeasterly winds, the threat for sub-tropical low pressure systems capable of producing heavy rainfall, similar to those experienced in late June and mid-July, is elevated, particularly in the north and east of the North Island.
Rainfall is about 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 most likely to be near normal in all other regions.
Oceanic ENSO-neutral conditions will very likely persist over the next three months. The long-standing climate drivers that have contributed to dryness over much of NZ are expected to influence our weather for at least the first half of the winter season.