December cool and cloudy

Cool December weather deprived Martinborough of sunshine and left Masterton with its third lowest temperature for the month in almost 70 years.

More northeast winds than normal affected New Zealand during December, producing warm, dry and sunny conditions in the southwest of the country and cool, wet and dull conditions in the north, said Niwa National Climate Centre principal climate scientist Dr Andrew Tait.

It was cooler than average (between 0.5°C and 1.2°C below average) for the month in parts of Wairarapa, Gisborne, Hawkes Bay and Marlborough and there was well above normal rainfall in most of the North Island and northern South Island.

Martinborough endured a near record low of 74 per cent of its average tally of sunshine hours for the month, recording 157 hours of sunshine, which was the second lowest total since records began in 1986.

Meanwhile, the mercury fell in Masterton on December 17 to a maximum air temperature of 11.5 C, which was the third lowest in the town since records began in 1943.

Centres throughout those areas received significant rain in the last two days of the year and according to Greater Wellington Regional Council figures, about 16 per cent of the average monthly rainfall of 599mm fell in the Tararua Ranges, as measured at the Angle Knob weather station.

The Ruamahanga River flow in the same two-day period - as measured at Waihenga, Wardell and Waiohine - had risen more than 10 times the rate of flow recorded for the 24 hours to 8am Thursday, after almost halving since December 21.

According to the Niwa outlook for January to March, seasonal rainfall is likely to be above normal for all North Island regions and in Nelson and Marlborough, and below normal or normal for the remainder of the South Island.

A moderate La Nina is in place in the tropical Pacific and should persist into early autumn 2012.

Air temperatures up to March are likely to be above average throughout the North Island and in the north, west and south of the South Island.

Weather warning

Wairarapa received a deluge of rain yesterday as wet weather moved across the North Island.

The MetService issued a heavy rain warning for the eastern hills of Wairarapa and the Tararua range, predicting heavy bursts throughout the day and into the evening.

The warning advised to watch out for rapidly rising streams and rivers, slips and surface flooding.

Southeast gales were also expected in the lee of the Ruahine and Tararua Ranges, with winds gusting 120km/h in exposed places.