Climate Summary for December 2013

A warm and dry month about central parts of New Zealand.

Temperature	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, and eastern parts of the South Island south of Christchurch, where near average temperatures (within 0.5°C of December average) were recorded.
Rainfall	Below normal rainfall (50-79 percent of December normal) or well below normal (less than 50 percent of December normal) was recorded across parts of Taranaki, the Central Plateau and the lower North Island, as well as northern Marlborough, the Mackenzie Country and parts of Central Otago, with near-record low rainfall totals observed in inland parts of the central and lower North Island. Well above normal rainfall (more than 150 percent of December normal) was observed in areas of Northland, the Coromandel Peninsula and Bay of Plenty, as well as around the Kaikoura coast and southwestern Southland.
Soil moisture	As at 1 January 2014, soils were drier than normal across western and central parts of the North Island, especially about western and central Waikato, the Central Plateau, as well as across and west of the Tararua Range. Soils were wetter than normal throughout the Coromandel Peninsula, the Bay of Plenty, and many eastern parts of the South Island.
Sunshine	A very sunny month (well above normal sunshine totals, more than 125% of December normal) for parts of Auckland and southern Northland, the southeastern North Island and the western South Island about northern Fiordland and the Westland glaciers. In contrast, below normal sunshine (75-90 percent of normal December sunshine) for northern and inland parts of Otago, and northern Southland.

Overview

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. Rainfall totals were typically near normal (within 20 percent of December normal) for the remainder of the country. As at 1 January 2014, soils were drier than normal across western and central parts of the North Island, especially about western and central Waikato, the Central Plateau, as well as across and west of the Tararua Range. Soils were wetter than normal throughout the Coromandel Peninsula, the Bay of Plenty, and many eastern parts of the South Island near Dunedin, and north of Ashburton. Soil moisture levels were nearer to normal for the remainder of the country.

Well above normal sunshine totals (more than 125% of December normal) were recorded in parts of Auckland and southern Northland, the southeastern North Island and the western South Island about northern Fiordland and the Westland glaciers. In contrast, below normal sunshine (75-90 percent of normal December sunshine) was recorded about northern and inland parts of Otago, and northern Southland. Sunshine was largely near normal elsewhere (within 10 percent of normal December sunshine).

Further Highlights:

• 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.

Full report

Full details of the December 2013 climate summary (PDF 541 KB)

Climate statistics table

Climate for December 2013 (PDF 63 KB)

For further information, please contact:

Dr Richard Turner

Research Meteorologist - Climate, NIWA Wellington

Tel. 04 386 0315