KEY POINTS:
As we all expected, 2006 was one hell of a weather ride, say new statistics.
Sometimes extreme, New Zealand's climate for 2006 featured one of the severest winter snowstorms in decades, a very windy spring, and a cold start to summer late in the year.
Oh, and it
was also quite sunny.
"The year was marked by too little rain in some places and too much in
others", said NIWA Principal scientist Dr Jim Salinger.
There were severe snowstorms, floods, destructive tornadoes, and windstorms. Excessive winter rainfall produced severe flooding in the Wairarapa, but it was very dry in Otago.
Of the main centres, Dunedin was dry and sunny, while Wellington and Christchurch were very wet.
"The year saw a swing from a La Nina to an El Nino climate pattern," said Dr Salinger.
"The first quarter of the year was dominated by weak La Nina-like characteristics in the equatorial Pacific, and frequent troughs of low pressure often over New Zealand. From September onwards weak–moderate El Nino conditions in the tropical Pacific had developed, with a noticeable increase in windiness, and more frequent south westerlies than normal over the country."
"There were numerous heavy rainfall events during 2006, about 18 of which produced floods.
"Other climate extremes included a summer heat-wave, four tornado incidents, three severe hailstorms, and many damaging windstorms."
The national average temperature in 2006 was 12.4 °C, 0.2 °C below the
1971 – 2000 normal. Thus, 2006 ended up very close to the 1971-2000
normal, as a consequence of very warm months (April, September) offsetting some very cold months (March, June, December).
In 2006 there were a number of records:
• The highest recorded extreme temperature of the year occurred
during a heat-wave in Central Otago toward the end of January. Alexandra
recorded maximum temperatures of 36 °C for three consecutive days from January 27 to 29 (unheard of in their historical record, commencing in 1930).
• The lowest air temperature for the year was -14.0 °C recorded at both Tara Hills, Omarama on 14 June and Fairlie on 28 June. The minimum
air temperatures were –10 °C or lower in parts in inland South
Canterbury and/or North Otago, on nine days between 14 and 29 June.
• April was the warmest since 1978.
• June was the equal coldest (with 1992) since 1972.
• September was the 3rd warmest on record.
• December was one of the coldest since 1945, approximately equal with Decembers 1946 and 2004.
• The highest recorded wind gust for the year was 180 km/h was recorded from the northwest, at Southwest Cape (Stewart Island) on September 2, a new record for a wind gust at that site. Mean wind speeds reached 128 km/h.
• The driest rainfall recording locations were Alexandra in central Otago with 266 mm of rain for the year, followed by Clyde with 286 mm.
• Of the regularly reporting gauges, the Cropp River gauge in Westland, inland in the headwaters of the Hokitika River, recorded the highest rainfall with a 2006 annual total of 11370 mm.
• Dunedin was easily the driest of the five main centres with 641 mm and Wellington the wettest with 1579 mm. Hamilton received 1155 mm, Auckland 1263 mm, and Christchurch 884 mm.
• Nelson was the sunniest centre in 2006, recording 2580 hours, followed by Blenheim with 2528 hours, and Tauranga with 2507 hours. Auckland was the sunniest of the five main centres with 2189 sunshine hours, followed closely by Christchurch (2169 hours), and Wellington (2159 hours). Dunedin recorded 1960 hours, and Hamilton 1996 hours.