Summer is changing: Quebec can't escape it

In short:

• The trend towards warmer summers is undeniable;

• The number of heatwave sequences is increasing;

• Heat and good weather go together.

Summer is changing

Remarkable fact in Quebec: Summers are changing. And that's just the beginning. The trend toward warmer seasons began in the late 2010s, and in fact, we haven't seen a cooler summer since 2017. Our expert Réjean Ouimet has studied the behavior of summer for nearly thirty years. Observation is concrete.

“Here we use the average temperature for three months from the main stations in southern Quebec,” explains meteorologist Régène Ouimet. The trend since the 1990s indicates two phenomena. First, the beginning of the period in the 1990s was mainly marked by cool summers. Conversely, recent summers have been hot, but not too hot.

A hundred years of change

A hot summer is defined as the number of days with temperatures of 30°C and above. Obviously, we must consider the southern part of Quebec to summarize this characteristic. By comparison, this observation is more significant for the metropolitan area than for Quebec. In the last 100 years, this extreme temperature has doubled.

“For Montreal, the average number of hot/sweltering days has practically doubled compared to 100 years ago,” confirms Régène Ouimet. From 7.5 days in ancient times, we have gone over 13 days in modern times. The 30 degree threshold is very difficult to reach in Quebec. »

A good year is a bad year

During summer in Quebec, there are petit crus and grands crus. In absolute terms, these seasons are often marked by suffocating heat wave sequences. Do we want more? For many, the answer is no. Also, this trend is increasing in recent years.

“If we look at the big years for Montreal, we see nine years, especially recently,” continues Réjean Ouimet. On the other hand, in years with an average number of warm days of 7 or less, this number is higher than in worst years. It has happened five times in the decade of the 1990s, none since 2017. In spite of everything, these days you can enjoy a milder summer. »