Science Centres: Climate

Overall, January 2010 was an unsettled month, being wet, slightly cool, and extremely cloudy. The month was characterised by lower pressures than normal over the country.

Percentage of normal rainfall, January 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 January 2010.

Rainfall

The most significant extreme weather event to impact on the country in January was the heavy rainfall event on January 31st, which affected the eastern and central North Island, as well as Waikato and Coromandel. A moist, easterly air stream brought heavy rain and embedded thunderstorms to these areas, causing flooding, slips, and road closures. Particularly hard hit were Gisborne and Hawkes Bay.  This one event produced most of the month’s rainfall total in these regions. More than double normal January rainfall was recorded in Gisborne, Hawkes Bay, the Wairarapa and in parts of the Waikato.  Above normal rainfall (between 120 and 150 percent of normal) was also recorded in most other regions of New Zealand.  The notable exception was Northland, which experienced well below normal rainfall (less than 50 percent of January normal) with severe soil moisture deficits continuing through to the end of January.  Other areas which experienced below normal rainfall (between 50 and 70 percent of January normal) were coastal Canterbury and north Otago.

Air temperature

January temperatures were near average (between -0.5°C and 0.5°C of average) across most of New Zealand.  The exceptions were small pockets of below average temperatures (between 1.2°C and 0.5°C below average) in Manawatu-Wanganui, the Wairarapa and southern Hawkes Bay, south Canterbury and in the Clutha district. The New Zealand national average temperature for January was 16.7°C (0.4°C below the long-term January average).

Sunshine

January sunshine totals were well below normal (below 75 percent of normal) over the lower North Island, and the entire eastern South Island, from Blenheim to Dunedin.  In contrast, Northland experienced a very sunny month, with sunshine totals between 110 and 125 percent of normal.  Elsewhere, sunshine totals were close to normal.

See our January 2010 climate summary.

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