August 2021 was the hottest on record for Montreal

It’s official!

August 2021 will go down in the record books as being the hottest on record for Montreal. The city recorded a monthly mean temperature of 23.6 degrees Celsius, which is 3.5 degrees warmer than normal.

Although the month started out with cooler temperatures, the trend reversed drastically on Aug. 9 as high heat and humidity moved in.

The city saw a five-day heat wave with daytime highs above the 30-degree mark from Aug. 9 to 13. A second heat wave, lasting 7 days, hit the city from Aug. 20 to 26 where numerous temperature records were broken.

(Downtown Montreal hit a record-breaking high of 35 degrees Celsius on Aug. 21, which is 2° higher than the previous record set in 1916.)

According to Environment and Climate Change Canada (ECCC), a similar heat wave this late in the summer in Montreal has only occurred once in 145 years of recorded temperatures (August 1948).

In Montreal, the temperature rose above the 30-degree mark in August for a total of 13 days, compared to an average of two or three days. The city also saw the humidex rise above 40 for a total of seven days, compared to an average of one day.

Montreal was not the only city to record its hottest August on record, places like Gaspe, Mont-Joli, Quebec City and Val-d’Or also saw record August heat.

The month of August was also marked by very little precipitation in Quebec. Less than 25 to 50 per cent of normal rainfall was recorded in many areas. Montreal only picked up 36.1 mm of rain, compared to a monthly average of 94.1 mm.


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