Science Centres: Climate

New Zealand climate in April 2006

Rainfall (click to enlarge).

Temperature (click to enlarge).

Rainfall was more than 300% of normal in parts of North and east Otago, and 200-250% of normal in many other places. Southern parts of Wairarapa, the Kaikoura coast, and coastal Southland were drier than usual.

Mean temperatures were about 1.5 °C above average throughout much of the North Island, with particularly warm conditions in parts of Auckland and Coromandel. Most South Island temperatures were 1 °C or more above average. The national average temperature of 14.6 °C (higher than March) was 1.2 °C above the 1971-2000 average.

For more information on the climate in April, visit the climate summaries page at www.niwascience.co.nz/ncc/cs/mclimsum_06_04

Soil moisture: persisting deficits Soil moisture (click to enlarge). The widespread rainfall of April lifted soil moisture levels almost everywhere. Many North Island soils were at saturation at the end of the month, apart from drier spots in Hawke’s Bay and southern Wairarapa. Significant end of March deficits in drier parts of the South Island were eliminated during April.

Many river flows above normal River flows (click to enlarge). River and stream flows were well above normal in many northern and central North Island districts, and in the north and southeast of the South Island. A number of catchments delivered flows in excess of 200% of normal. Normal flows occurred in the South Island hydro catchments.

February 2006 to April 2006: the climate we predicted and what happened

(click to enlarge).

Rainfall

Rainfall was higher than predicted in the north of the North Island, and lower than predicted in the southwest of the country

(click to enlarge).

Air temperature

Air temperatures were average or above average as predicted in many areas, but lower than expected in parts of the west and south of the South Island.

(click to enlarge).

River flows

Stream flows were above normal in many northern and central North Island catchments, and in the north and southeast of the South Island. Western South Island flows were lower than normal.

The three outcome maps give the tercile rankings of the rainfall totals, mean air temperatures, and mean river flows that eventuated from February to April, in comparison with the forecast conditions.

As an approximate guide, middle tercile rainfalls typically range from 80 to 115% of the historical normal, and middle tercile temperatures range about the average by plus or minus 0.5 °C.