September's climate
New Zealand climate in September 2006
September was a month of climate extremes with record low rainfall and high mean temperatures at many locations. Rainfall was low throughout much of New Zealand, especially in the east from Wairarapa to Canterbury. Some Canterbury locations recorded 10% of normal rainfall or less.
It was the third warmest September on record, with a national average temperature of 11.6°C, 1.2°C above normal. Temperatures were especially high in the east from Marlborough to Otago.
For more information on the climate in September, visit the climate summaries page at www.niwascience.co.nz/ncc/cs/mclimsum_06_09
Lower soil moisture storage Soil moisture (click to enlarge). During September, there was a net loss of moisture in soils across most of the country, but particularly in the north and east of the North Island, and in Nelson, the South Island east coast, and inland Otago. |
Mostly low river and stream flows River flows (click to enlarge). September stream flows were below normal over most of the country, but above normal flows occurred in the southwest of the South Island. |
July 2006 to September 2006: the climate we predicted and what happened
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Rainfall
Rainfall was lower than expected in the north of the North Island, and in the north and east of the South Island. More rain fell in the southern North Island than predicted.
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Air temperature
The temperature outlook was correct in most regions, apart from the warmer than expected conditions in the north of the South Island.
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River flows
North Island stream flows were above normal in the east, and normal in central areas, as predicted, but below normal in the north. South Island stream flows were lower than predicted in the north and in Otago.
The three outcome maps give the tercile rankings of the rainfall totals, mean air temperatures, and mean river flows that eventuated from July to September, 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.