Current climate: December 2015
During December 2015, strong El Niño conditions continued in the Tropical Pacific. In New Zealand this contributed to the prevalence of high pressure over and to the west of the country while lower pressure than normal existed to the east of New Zealand. This pressure pattern resulted in more south-westerlies than normal over the South Island and more southerlies than normal over the North Island.
The dominance of high pressure throughout December meant that the month as a whole was very dry with several locations around the country observing record or near-record low December rainfall totals. Less than half of normal rainfall was observed for the majority of the North Island and below normal rainfall (50-79% of the December normal rainfall) was recorded across most of the South Island. No locations recorded above normal rainfall (120-149% of the December normal rainfall) and the only places to observe near normal rainfall (within 20% of the December normal) were parts of Southland and southern Canterbury.
December temperatures were largely near average (-0.50°C to +0.50°C) across New Zealand. Below average temperatures (-1.20°C to -0.51°C) were recorded along the east coast of the North Island from Gisborne through to south Wairarapa as well as north-eastern parts of the South Island.
A very sunny December with above (110-125%) to well above (>125%) normal sunshine experienced around the country. A number of locations observed record or near-record sunshine hours for December.
The lack of rainfall, following a dry November, meant soil moisture levels continued to deplete around the country throughout the month, particularly in the North Island. As of 1 January 2016, soil moisture levels were below normal for the time of year for the entire country with the exception of the Auckland region and Coromandel. The driest soils when compared to normal existed throughout the Waikato and Taranaki regions as well as parts of the Bay of Plenty.