Science Centres: Climate

Overall, October 2010 was extremely sunny and very dry in most regions. More anticyclones (‘highs’) covered New Zealand than is typical for the time of year, resulting in a rather settled climate during the month. The exceptions were an extremely cold southerly event which affected the country on the 11th and 12th, and a subsequent wet period for the east coast of the North Island between the 13th and 15th.

Percentage of normal rainfall, October 2010.

End of month water balance in the pasture root zone for an average soil type, where the available water capacity is 150 mm.

Departure from average air temperature for October 2010.

Rainfall

October rainfall was more than double normal (at least 200 percent) in Gisborne and Hawkes Bay.  But for the remainder of the country, it was very dry, reflecting the prevalence of anticyclones.  Rainfalls were well below average (less than 40 percent of normal) across much of the North Island (excluding the east coast).  It was the driest October in Nelson since records began in 1941, with less than 10 percent of normal rainfall.  Elsewhere in the South Island it was rather dry, with rainfall between 50 and 80 percent of normal, except for Southland, which experienced closer to normal rainfall.  By the end of October, larger than normal soil moisture deficits had developed in much of Northland, coastal Nelson, mid Canterbury, and North Otago.

Air temperature

Extremely cold temperatures affected the country on the 11th and 12th, followed by unusually warm spells on the 16th and 30th.  Even with the extreme swings in temperature, monthly mean temperatures were near average (within 0.5°C of average) for much of the country.  The exceptions were above average temperatures recorded in the southwest of the South Island (between 0.5°C and 1.2°C above average), and below average temperatures (between 0.5°C and 1.2°C below average) in Gisborne, Hawkes Bay, the Wairarapa, parts of Buller, the Sounds, and around Kaitaia.  The New Zealand national average temperature was 11.7°C (0.5°C below the 1971–2000 October average). 

Sunshine

Sunshine totals were well above average (more than 125 percent of normal) across most of the South Island, and the north and west of the North Island.  Many October sunshine records were broken.  It was the sunniest October since records began at Kaitaia, Te Kuiti, Taumarunui, Takaka and Nelson, Timaru, Dunedin, and Balclutha.  Sunshine totals were also slightly up for the eastern North Island (with sunshine totals between 100 and 115 percent of normal), despite the much higher than normal October rainfall there.

See our October 2010 climate summary

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