Outlook and outcome – June to August 2002

Rainfall was generally as expected over the South Island as well as the central North Island, but wetter than forecast in the east and parts of the north of the North Island.

Air temperatures were normal or above normal, as was predicted, for all districts except the east of the North Island, where normal temperatures were predicted but the winter temperature outcome was above normal.

River flows were normal in Waikato, Nelson, and coastal Otago and Southland, and below normal in Marlborough and Canterbury, as they were predicted to be. Flows were higher than predicted in other areas, and below normal in parts of Bay of Plenty.

The outcome maps shown here give the tercile rankings of the rainfall totals and mean temperatures that eventuated for these months. Terciles were obtained by dividing ranked June to August data from the past 30 years into three groups of equal frequency (lower, middle and upper one-third values) and assigning the data for the present year to the appropriate group. (Click to enlarge)

As an approximate guide, middle tercile rainfalls often range from 80 to 115% of the historical average. Middle tercile air temperatures typically occur in the range of the average plus or minus 0.5°C.