Outlook and outcome – May to July 2002

Rainfall was as forecast for many areas. It was higher than predicted in parts of the east of the North Island, and over coastal south Otago and Southland.

Air temperatures were as expected in all regions except the south and west of the South Island, where they were higher than predicted.

River flows were above what was expected in much of the North Island, and in Buller and Southland. Some central South Island regions had normal to below normal flows rather than the normal flows that were predicted.

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 May to July 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.