December 2013 Climate Summary
December 2013 Climate
December 2013 was characterised by mean sea level pressure anomalies that were well below normal across New Zealand, with particularly negative anomalies extending south-westward into the Australian Bight and the southern Ocean.
Positive pressure anomalies were situated to the south-east of the country. These regional pressure patterns resulted in a weak northerly flow anomaly across the North Island, with wind patterns of variable nature across the remainder of the country.
Temperatures were above average (0.5-1.2°C above December average) or well above average (more than 1.2°C above December average) throughout much of New Zealand. The exceptions were parts of the Far North, Waikato, Bay of Plenty, eastern Canterbury and Otago, and Southland, where near average temperatures (within 0.5°C of December average) were recorded.
The nation-wide average temperature in December 2013 was 16.6°C, (1.0°C above the 1971-2000 December average from NIWA’s seven-station temperature series which begins in 1909).
Rainfall was below normal (50-79 percent of December normal) or well below normal (less than 50 percent of December normal) for parts of Taranaki, the Central Plateau and the lower North Island, as well as northern Marlborough, the Mackenzie Country and parts of Central Otago.
In contrast, well above normal rainfall (more than 150 percent of December normal) was observed in northeastern parts of the North Island, including areas of Northland, the Coromandel Peninsula and Bay of Plenty, as well as around the Kaikoura coast and southwestern Southland. Rainfall was above normal (120-149 percent of December normal) across most remaining parts of the northeastern North Island and the eastern South Island.
The highest temperature was
34.2°C, recorded at Clyde on 5 December.
The lowest temperature was -1.2°C, observed at Middlemarch on 1 December.
The highest 1-day rainfall was 175 mm, recorded at North Egmont on 4 December.
The highest wind gust was 152 km/hr, observed at Cape Turnagain on 21 December.
In December 2013, Wellington was the driest and sunniest, Auckland was the warmest, Dunedin was the coolest and cloudiest, and Tauranga was the wettest of the six main centres.
For full summary and regional breakdowns please see attachment.