This is officially one of the coldest springs and starts to summer on record for Whistler, although that's not saying much with Environment Canada's online data for the resort only going back as far as 2005. Still, the average temperatures have been cooler than average and there have been fewer warm days.
"I don't think we have a good explanation for any of this," said Environment Canada meteorologist David Jones. "Heading into the winter we had two things loading the dice in favour of colder conditions for winter and spring. It didn't work out for winter, which was very average for temperatures, but spring has been miserable - almost record-setting cold."
While a lot of meteorologists point to La Nina, El Nino, the Pacific Decadal Oscillation and other factors in making long-term forecasts, Jones said these things have a small influence at best - maybe 10 or 15 per cent, while the other 80 per cent is the result of at least six other factors.
But while the causes are difficult to explain, Jones said, the effects are obvious from the satellite pictures.
"The direct reason of why it's been so cold - or has been because things did change at the beginning of June, which is very average... if not busting out with sunshine - is these cold pools of air that keep swinging down from the Gulf of Alaska and the storms are cresting over us (in southwest B.C.) way too frequently," said Jones.
The average high temperature for the month of June (June 1 to June 26) has been 17.5 C, while the average low is 7.4 C for a mean temperature of 12.4 C.
Comparatively, in June 2010 - also colder than average - the average high was 17.7 C and the average low 7.8 C, with a mean of 12.8 C.
In other words, the average mean temperature this year 0.4 degrees cooler than in 2010.
In 2009, the average high was 21.8 C, the average low 8.4 C and the mean 15.1 C. In 2008, the numbers were 18.4 C, 6.5 C and 12.5 C respectively; in 2007 it was 17.8 C, 7.1 C and 12.5 C; in 2006 it was 21.8 C, 7.5 C and 14.7 C; in 2005 (when daily records were first kept, it was 19.5 C, 8.7 C and 14.2 C respectively.
Some records are incomplete or have errors that skew the average slightly.
Put another way, June 2011 is so far trending to be the coldest in the past seven years.
As for days over 20 degrees, there have been just seven of them between June 1 and June 20, 2011. There were nine in the same period of 2010 and 16 in 2009. There were six days above 20 in the first 27 days of June 2008 but four of the last five days were above 20 C (three of them above 30 C) which we won't match this year. There were eight days over 20 C in 2007, and 10 in 2006.
May was also a cooler month than we've seen in six years of data. In 2011 the average high was 13.4 C, the average low 3.3 C and the mean 8.4 C, with three days above 20 C. In May 2010, averages were 15.0 C, 3.0 C and 9.0 C respectively, with six days over 20 C. In 2009, averages were 16.5 C, 3.4 C and 10.0 C respectively, with nine days over 20 C. In 2008, the averages were 17.4 C, 4.8 C and 11.1 C respectively, with eight days over 20 C. In 2007, the averages were 17.0 C, 2.6 C and 9.8 C with eight days over 20 C. In 2006, the averages were 17.7 C, 3.2 C and 10.5 C respectively with 10 days over 20 C.
According to the Environment Canada Weather Office, the South B.C. Mountains had the highest "cool" rating in Canada this spring with average temperatures 0.9 C below normal.
While it's cooler than normal it could be worse. There was extensive flooding in the prairies and in Quebec this spring, as well as in the northern U.S. The southern U.S. suffered one of its worst tornado season on record, followed by hotter than average temperatures and drought.
As for the summer forecast, it's been reported that the summer and early fall will be hotter and drier than average, but Jones is skeptical of any long range forecasts. The good news, however, is in the short-term forecast. "Summer may arrive this weekend for at least three or four days and perhaps longer, and this could be the start of some summer momentum with these ridges of high pressure that persist and persist," he said.
