A Dismal Summer?

Some Wellingtonians have been muttering about the dismal weather we have been experiencing this summer.

Sunday 24th January 2010

After yet another cold southerly blast, Wellingtonians have been muttering about the gloomy, foggy days and generally dismal weather we have experienced so far this summer. Certainly the valley of Tawa has been fog-bound on several occasions during December and January, and we seem to have had a lot of rain. Grumpy gardeners report stunted capsicums, shredded tomato plants and toppled corn rows, while commercial lawn-mowers are frustrated by the continued growth and the shortage of fine days on which to keep things trimmed while still enjoying a holiday break themselves.

A look at the statistics gathered by Tawa Weather tends to confirm this impression.

Tawa Weather has been collecting automated weather statistics since 2005, and the records show that December 2009 was the second coldest of the five years, with an average temperature of 15.6 ºC. The coldest was December 2006 with an average temperature of 14.4 ºC. The wettest December was in 2008 when 96 mm of rain was recorded, runner-up was 2006 with 69 mm of rain. Last month, 60 mm of rain was recorded, putting it third equal with December 2007.

Over the five year period from January 2005 to January 2009, the coldest January was in 2007 with an average temperature of 16.9 ºC. Runner-up was January 2005 with an average temperature of 17.7 ºC. The roles were reversed with respect to rainfall with January 2005 wettest with 99 mm and January 2007 second with 66 mm of rain.

With a quarter of January 2010 left to run the pecking order could easily change. So far, January 2010 is the coldest of the six-year period with an average temperature of 16.1 ºC. It is in second place in the rain stakes with 82 mm of rain to date, easily surpassing January 2007 and nipping at the heels of January 2005.

In terms of the number of days when more than a millimetre of rain fell, December 2005 and December 2006 shared the most rain days over the five-year period with thirteen rainy days. January 2007 sported 10 rainy days, ahead of January 2006 as runner-up when rain fell on 7 days during the month. Tawa Weather has recorded 10 rain days to the end of January 23rd 2010.

Averages are all and well, but what we remember are the baking hot days and the bone-chilling southerlies that had us hauling heaters out of storage and fumbling in the cupboard for a duvet in the middle of the night.

Over the five year period to the end of 2009, the coldest December temperature was recorded in 2008. The temperature dropped to 6.4 ºC on the 22nd. This was just below the lowest temperature for December 2007, which was 6.5 ºC on the first. Locals might remember that New Year 2007/2008 was particularly dreary. Horizontally-driven rain fell steadily from New Year’s Eve under the tender ministrations of a chill southerly sending us fossicking in wardrobes for jackets, raincoats and jerseys. One compensation was the holiday release of a couple of classic movies including The Queen which had movie theatre tills a-ringing as people fled indoors.

Moving on to January, the coldest January temperature at Tawa in the five-year period was recorded on the 4th of January 2007 when the thermometer dropped to 6.2 ºC. Runner-up was that stormy New Year’s Day in 2008 when the mercury dropped to 7.5 ºC. Rain marred ten days in January 2007 and seven days in 2006.

At the other end of the temperature spectrum, the mercury shot up to 27.7 ºC on the 9th of December 2007, and 27.1 on the 14th in 2005. January’s high was 30.3 ºC on the 29th in 2008, closely followed by 29.8 on the 12th of January 2007.

With a quarter of January 2010 left to run, the statistics to date are a mixed bag. The lowest temperature so far was 9.3 ºC on the 14th and the highest 26.2 ºC on the 20th neither of which stand out in comparison with the previous five Januarys. We have had 10 rainy days at Tawa so far this month, equalling January 2007. Rainfall is 82 mm to the end of the 23rd, putting the month in second place to January 2005 when 99 mm was recorded. The average temperature so far is 16.1 ºC, making it the coolest January in the six year period, followed by January 2007 at 16.9 ºC.

It just goes to show that there is no real measure of a “good summer.” Is it the number of sunny days, absence of cold days, minimal rain, spectacular highs, or absence of wind? Statistically, the average temperature is probably the best measure, but we will always remember the extremes like downpours, biting southerlies or the day the lead-head nails on the roof melted.

All is not lost, however, Typically our weather doesn’t improve until after New Year, and February is generally our most pleasant summer month. Running a few weeks late might mean that we have one of those nice “Indian summers” that extend into March. Hope springs eternal, as they say.

You might feel a bit better by comparing this summer’s low points with the summer storm that blasted New Zealand in 1933.

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