Current Climate - October 2013

October 2013 was characterised by mean sea level pressure anomalies that were strongly negative around the New Zealand region, particularly in the south-western sector.

These regional pressure patterns resulted in frequent west to south-west flows across New Zealand. These flows resulted in considerable October rainfall totals along and west of the Southern Alps, and frequent episodes of warm air temperatures to the east of the Southern Alps due to the foehn effect. 

Rainfall

Considerable variations in rainfall anomalies were observed across the country.  Well below normal rainfall (less than 50 percent of October normal) was recorded throughout Northland, Auckland and Gisborne.  Rainfall was either well below normal or below normal (50-79 percent of October normal) in Waikato (with the exception of the southwest of the region), Bay of Plenty and Hawke’s Bay.  Below normal rainfall was also recorded in coastal mid-Canterbury and north-eastern Marlborough.  In contrast, well above normal rainfall (more than 150 percent of October normal) occurred near and west of the Southern Alps, and in south-western parts of Southland, eastern Central Otago and northwest Tasman.  Rainfall was generally above normal (120-149 percent of October normal) for the remainder of New Zealand, with the exception of rather limited areas including Dunedin, the Canterbury Plains, Marlborough and parts of the south-western North Island where near normal rainfall (within 20 percent of October normal) was recorded.  As at 1 November 2013, soils were drier than normal in north-eastern parts of New Zealand, especially about Northland, northern Auckland and coastal Bay of Plenty.  In contrast, soils were wetter than normal about eastern Southland and Otago, the Southern Lakes, northern Canterbury and Whanganui.  Soil moisture levels were mostly near normal for the remainder of the country.

Temperature

Near average temperatures (within 0.5°C of October average) were recorded in western and southern parts of Southland and Otago, the Canterbury High Country, Westland, northwest Tasman, northern Taranaki, and northern parts of Waikato, Auckland and Northland.  Above average temperatures (0.5-1.2°C above October average) occurred throughout most remaining areas of New Zealand, with well above average temperatures (more than 1.2°C above October average) recorded in parts of Hawke’s Bay and north Canterbury near Kaikoura.  The nation-wide average temperature in October 2013 was 12.9°C, (0.8°C above the 1971-2000 October average from NIWA’s seven-station temperature series which begins in 1909).

Sunshine

October was a very sunny month for Northland, Gisborne, Hawke’s Bay and mid-Canterbury (well above normal sunshine totals, more than 125% of October normal).  Above normal sunshine (110-125 percent of normal October sunshine) occurred throughout central parts of the North Island, Bay of Plenty and northern Auckland.  Below normal sunshine (75-90 percent of normal October sunshine) was recorded for the northwest and southwest of the South Island.  Sunshine was near normal elsewhere (within 10 percent of normal October sunshine).