Science Centres: Climate

In April 2011, New Zealand was affected by more southeast winds than usual. These produced extremely high rainfalls in the east of the North Island, as well as on the Kaikoura coast. The southeast winds also resulted in below average April temperatures in most eastern areas, but gave a very sunny month for the West Coast of the South Island.

Rainfall

Treble normal (more than 300 percent) April rainfall was experienced in Hawkes Bay.  Most of this rain fell in two days (between 26 and 28 April), and a State of Emergency was declared there on 28 April, due to flooding and slips.  Several coastal Hawkes Bay settlements were evacuated after being completely cut off.  Well above normal rainfall (more than 150 percent of April normal) was also recorded in Auckland, Waikato, Bay of Plenty, inland Gisborne, Wairarapa, Wellington, Kapiti Coast, the Manawatu, south Taranaki, the Kaikoura coast, and south Canterbury.  In contrast, it was a relatively dry month for the west and south of the South Island (with rainfalls between 50 and 79 percent of normal).  At the end of April, soils were unusually wet for the time of year for almost all of the North Island, as well as in many eastern regions of the South Island.

Air temperature

April mean temperatures were below average (between 1.2°C and 0.5°C below April average) in most eastern areas of the country; Hawkes Bay, Wairarapa, Wellington, Kaikoura Coast, much of Canterbury and coastal Otago, as well as some inland sites along the South Island Main Divide.  Unusually cold events for the time of year occurred in a southerly airstream on 18 April, and in the wet, southeast event on 27-28 April.  The New Zealand national average temperature in April was 13.0°C (0.4°C below the 1971–2000 April average).  

Sunshine

Sunshine totals in April were below normal (between 75 and 90 percent of normal) for much of the North Island (except Northland), as well as in Nelson and Marlborough.  In contrast, it was a very sunny month for the West Coast of the South Island (with totals around 125 percent of normal), as well as for the far south. 

See our April 2011 climate summary

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