Outlook: December-February 2018

December 2017 – February 2018 temperatures are forecast to be above average, with high confidence, for all regions of New Zealand (60% to 70% chance).  Coastal water temperatures around New Zealand are forecast to remain above average over the next three-months period.

For December 2017 – February 2018 rainfall totals are most likely (45% chance) to be above normal in the north of the North Island.  Summer rainfall is about equally likely to be near normal (35% chance) or above normal (40% chance) for the east of the North Island.  For the west of the North island, December 2017 – February 2018 rainfall amounts are most likely to be in the near normal range (45% chance).  Near normal rainfall amounts are most likely for the north of the South Island (40% chance). Below normal rainfall is most likely for the west of the South Island (45% chance).  Rainfall totals for the next three months are about equally likely to be below normal (35% chance) or near normal (40% chance) for the east of the South Island.  

December 2017 – February 2018 soil moisture levels and river flows are most likely to be above normal (40% chance) in the north of the North Island and most likely (40% chance) to be near normal in the west of the North Island. Soil moisture levels and river flows are equally likely to be near normal (35% chance) or above normal (35% chance) in the east of the North Island.  In the north of the South Island, soil moisture levels and river flows are most likely to be in the near normal range (40% chance) with below normal soil moisture levels and river flows most likely (55% chance) for the east and west of the South Island. 

Graphical representation of the regional probabilities, Seasonal Climate Outlook, December-February 2018.