Current Climate - April 2012

April was characterised by markedly high pressures over the South Island and to the east of the Chatham Islands, with prevailing easterly winds (and high pressures) over the North Island. The frequent anticyclones ('highs') during the month resulted in very dry and extremely sunny conditions for April, for many regions of the country. 


April rainfall was less than half of normal for Fiordland, Southland, Otago, the Lakes District, south Canterbury, Auckland, Coromandel, Western Bay of Plenty, Waikato, Taranaki, Taupo, and Manawatu-Wanganui.  Central Otago was particularly dry, with rainfall less than a quarter of April normal there.  Rainfall was also below normal for Westland, Nelson, and Northland. In contrast, rainfall was close to normal in north Canterbury, the Kaikoura coast, the Wairarapa and Napier. The Gisborne region experienced a wet April. At the end of April, soils were much drier than normal for the time of year between Wanganui and the Kapiti Coast, and in Southland. 


Mean temperatures for April were well above average in Southland and Fiordland.  It was also rather warm along the West Coast, as well as for Bay of Plenty, Coromandel, Waikato, and parts of Auckland and Northland (with mean temperatures between 0.5°C and 1.2°C above April average).   Elsewhere, mean temperatures were generally close to average. Notably, afternoon (maximum) temperatures were extremely high for the south and west of the South Island, Nelson, between Wanganui and Palmerston North and northwards to the Waikato, the Central Plateau, Bay of Plenty, and parts of Auckland – reflecting the settled and sunny weather associated with the April anticyclones.  The nation-wide average temperature in April was 13.7°C (0.3°C above the 1971–2000 April average), using NIWA’s seven-station temperature series which begins in 1909.


It was extremely sunny across much of the South Island, as well as in many western and central regions of the North Island, with sunshine totals at least 125% of April normal.  Sunshine totals were the highest on record for April for Te Kuiti, Taumarunui, New Plymouth, Nelson, Cheviot, Lake Tekapo, Dunedin and Cromwell – and some of these locations experienced an astounding one-and-a-half times typical April sunshine totals. Sunshine totals were closer to normal for the eastern Bay of Plenty, Gisborne, Northland, Wellington and the Wairarapa. 

Percentage of normal rainfall, April 2012
End of month water balance in the pasture root zone for an average soil type, where the available water capacity is 150mm.
Departure from average air temperature for April 2012.