Current Climate - March 2014

March 2014 was characterised by anomalously high pressure over much of New Zealand, and in particular, over the South Island. In spite of the overall surface pressure regime being abnormally high, there were periods of lower pressure, which contributed to the occurrence of a few moderate-to-heavy rainfall events during the month.

Rainfall

For the most part, with regards to rainfall on the North Island, March picked up where February ended as abnormally dry conditions were experienced for the start of autumn. Well below normal rainfall (less than 50% of March normal) occurred for a sizeable part of the North Island between the Manawatu-Wanganui and Auckland regions. In fact, numerous locations placed in their top three for driest March on record. This includes Hamilton, which experienced its second driest March on record with only 6 mm of rain accumulating for the month (records go back to 1935). There were patches of near normal (within 20% of normal) rainfall on the North Island including the Wellington and eastern Hawke's Bay regions. Isolated areas of above rainfall (120-149% of normal) or well above normal rainfall (more than 149% of March normal) occurred on the hills around the Coromandel Peninsula, largely due to the impacts of ex-tropical cyclone Lusi during the middle part of the month.

On the South Island, the vast majority of the West Coast, Fiordland and Stewart Island recorded below normal rainfall (50-79% of March normal) or well below normal rainfall. Conversely, above normal to well above normal rainfall was experienced for eastern areas of the Canterbury and Otago regions, where Christchurch and Dunedin reported well above March rainfall. In fact, Christchurch (Riccarton) endured its wettest March on record (records go back to 1863). Additionally, of the 200mm that fell during the month at Christchurch (Riccarton), 123mm accumulated in one day (4 March), which is now the greatest one day March rainfall on record for the city. Otherwise, near normal rainfall was the theme for much of the central portion of the South Island.

Temperature

Temperatures during the first month of autumn in New Zealand were near average (within 0.5°C of March average) for a large part of the country. Notable exceptions include pockets of below average temperatures (0.5-1.2°C below March average) for coastal areas from the southern Gisborne, northern Hawke's Bay and far southeast coastal Manawatu-Wanganui regions. The March temperature regime for South Island was comparable to the North Island with near average values for March. One exception, however, was a sizeable area of below average temperatures along coastal sections of the South Island from the Marlborough region south through to the northern Otago region. Within this zone there were even spotty areas of well below normal temperatures (greater than 1.2°C below March average) particularly in and around the Banks Peninsula. The nation-wide average temperature in March 2014 was 15.3°C (0.5°C below the 1971-2000 March average from NIWA's seven station temperature series which begins in 1909).

Sunshine

The lack of rainfall for much of the North Island was combined with an abundance of early autumn sunshine for much of the island. In fact, above normal sunshine (110-124% of March normal) was recorded from the Auckland region south through much of interior and eastern portions of the North Island. It was an especially bright start to autumn for the Waikato region where well above normal sunshine (more than 125% of March normal) occurred. Slightly below normal sunshine was experienced in Wellington. For the South Island, near normal sunshine occurred (within 10% of March normal) for most areas. Outliers include Dunedin and north-central portions of the South Island where sunshine was above normal.