December Climate Comment and 2018 Year in Review

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Highway 6 closure on January 30th, 2019. The cold and snowy January seemed to be making up for the unusually warm December we experienced.
Submitted by Bill Caulfeild-Browne

December was an unusually warm month with temperatures 2.2C above normal. In fact the mean temperature was only a degree-and-a-half cooler than November, which had been precisely 2.2C below normal.
Otherwise the month was rather unremarkable. Precipitation was pretty much on the long-term average at 64 mm. Much of this fell as rain rather than snow – 18 mm. on the 2nd when the thermometer read 5C and another 8 mm. on the 21st when it was also above freezing. It was barely a white Christmas as most of the rest of the precipitation fell after the 25th.
Winds were a little less aggressive than usual – at an average speed of 10 kms/hr they were less than either October or November. Even the highest wind was only 64 kms/hr whereas November was well over 70 kms/hr.
Full sunshine was evident nine days of the month though only seven were sunny from dawn til dusk.
2018 as a whole was a touch warmer than normal though well within one standard deviation. The mean annual temperature was 6.3C against a mean for the 20th century of 6C. This simple statistic, though, is quite misleading – there were dramatic swings in the weather during the year. Most significant were a warm February (2C above normal) and a very cold March (3.5C below normal.) This cold March extended winter rather more than most of us liked.
The summer months were marginally warmer than expected, particularly August at 1.8 C above average. Unfortunately they started with something of a drought in June which continued through July, resulting in fire bans here and serious fires on the other side of Georgian Bay – serious enough that we were choked with smoke here on several days when NE winds blew.
The drought ended in spectacular fashion at the end of August when we set a record for the second wettest August since 1914. Alas, it came too late for a lot of our gardens which had dried right up by then.
That drenching resulted in the year as whole being a wet one. Total precipitation was 940 mm. which is nearly 200 mm. more than average. Only 2013 and 2014, with their 1086 mm. and 1044 mm. respectively, materially exceeded last year.
The lowest the mercury sank to in 2018 was -20.7C on January 6th and the highest was 32C on July 20th.
We’re having a pretty cold January as I write this on the 27th. Last week we matched last year’s low of -20.7C and tonight is forecast to be even colder. More on that next month!