September 2020 covered the complete weather spectrum.
Chris Carss, a volunteer weather observer for Environment Canada at his Chemainus home, noted it was a month of slightly diminished sunshine, sometimes accompanied by smoke, that was temporarily replaced by thunder and downpours of rain late in the month.
“It might not have been quite the vintage September that was looking possible a few weeks ago, but days with temperature highs of 20 Celsius or over managed to outnumber the cooler days by just enough to keep the summer weather going at least intermittently until early October,” he added.
“Not surprisingly, most of the sunny warm weather came during the first 11 days of the month. Smoke generated by wildfires mostly south of the Canada-U.S. border resulted in some dangerously poor air quality during the first half of September, but at least it didn’t obscure the sun as it has done in some previous years. Intermittent spells of wet weather during the second half of the month helped clean the air and only blotted out the sun part of the time.”
There was a four-day spell of unusually stormy weather right after the fall equinox that dumped about two months worth of rain.
“However, it didn’t last long enough to normalize our total number of wet days, which remained a bit below the average for the month,” Carss pointed out. “The storms may have led some to believe the calendar had nailed the end of summer even more accurately than it had signaled the beginning of summer back in June.
“But that kind of synchronicity between the calendar and the weather is uncommon, and those who enjoy our warmest season were treated to one last shot of summer that brought more warm sunny weather, but also more smoke, that lasted until Oct. 3.”
The mean daily maximum temperature for September in Chemainus was 21.7 degrees Celsius, more than a degree above the normal of 20.1 C. The mean daily minimum was also well above the normal, 13.0 C compared to 11.4 C.
The month’s extreme maximum of 30.0 C occurred on Sept, 10, with the extreme minimum of 9.5 C on Sept. 27.
There were 16 mostly or partly sunny days in September. The normal is 18 days with sunshine.
Of the 14 mostly days, seven had rainfall – two less than the normal of nine.
September’s total rainfall of 96.2 millimetres was far above the normal of 40.8 mm.
With the autumn weather now underway, Carss noted daytime temperatures for October will be running close to seasonal normals (around the mid-teens Celsius) with near normal sunshine, but possibly as few as eight days with rainfall.
“This could mean as little as half our normal total rainfall for the month, the good news being that the growing season for most water dependent garden plants is now over or in decline,” he observed.
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