A moderate La Niña is in place in the tropical Pacific and should persist into early autumn 2012. For the January to March season, mean sea level pressures are likely to be above normal across the South Island, but below average to the north of New Zealand, with more north-easterly air flow than normal over the North Island.
Sea surface temperatures
Sea surface temperatures in the New Zealand region are likely to be near average or above average.
Differences from average global sea surface temperatures for 4 to 31 December 2011. Map courtesy of NOAA Climate Diagnostics Centre (http://www.cdc.noaa.gov/map/images/sst/sst.anom.month.gif).
Monthly values of the Southern Oscillation Index (SOI), a measure of changes in atmospheric pressures across the Pacific, and the 3-month mean (black line). SOI mean values: December SOI +2.3; October to December average +1.4.
Differences from normal December surface temperatures in the seas around New Zealand.