Current climate – May 2015

May 2015 was characterised by air pressures which were well below normal in the Tasman Sea, with below normal pressures extending over New Zealand. This circulation pattern was accompanied by a westerly flow anomaly over New Zealand. This flow anomaly was clearly reflected in the distribution of rainfall anomalies observed across New Zealand.

Rainfall

Rainfall was well below normal (< 50%) or below normal (50-79%) for eastern parts of New Zealand from Gisborne all the way south to North Otago.  Rainfall was well above normal (> 149%) or above normal (120-149%) for western parts of the South Island, the Southern Lakes, southwestern and western parts of the North Island, and eastern Bay of Plenty. 

Temperature

May temperatures were above average (+0.51°C to +1.20°C) for parts of Southland, Otago, Canterbury, Wairarapa, Whanganui and Southern Taranaki. May temperatures were below average in isolated parts of central Hawke’s Bay and western Waikato (-0.51°C to -1.20°C).

Sunshine

May sunshine was abundant for eastern parts of New Zealand including the eastern Bay of Plenty, Gisborne, Hawke’s Bay, Wairarapa, Marlborough, Canterbury and Otago where May sunshine was typically above normal (110-125%) or well above normal (> 125%).

Soil Moisture

As of 1 June 2015, soil moisture levels were below normal for this time of year for East Cape, coastal Wairarapa, southern Marlborough and eastern parts of Canterbury. It was especially dry about North Canterbury where soils were considerably drier than normal for this time of year.