It feels like June. It was the end of September. A warmer and drier month than seasonal norms sums up Environment Canada. In the parks and rivers of the metropolis, on the last day of September, the sun brings joy from children to adults.
“It’s truly a gift, today and all week too,” said François, returning from a trip to Mount Royal with his partner, Jean.
Photo by Josie Desmarais, The Press
François and Jean meet in the park of Jean-Mans
Around him, people stroll in Jean-Mans Park. Some sunbathe in swimsuits. Guitar music plays. The smell of barbecue wafts in. The sun floods the flowerbeds through the leaves of the trees that are beginning to color. Along the Lachine Canal, paddleboarders rub shoulders with fishing families.
The mercury touched a comfortable 23°C in Montreal on Saturday. In the coming days, with the arrival of October, it should touch 26°C before falling again at the weekend.
This September was an average of 2 to 3 degrees warmer than seasonal norms, explains Dominique Martel, a meteorologist with Environment Canada. This difference is particularly significant in Montreal compared to an average of 18.5°C, compared to 15.5°C in seasonal terms.
The meteorologist notes that similar conditions were experienced across Quebec. In Trois-Rivières, where the normal temperature is 14°C, we observed 16.3°C. On the Quebec side, the mercury averaged 16.2°C, compared to the usual 12.7°C. In Saguenay, where the normal temperature is 12°C, we observed 15.4°C. In Mont-Jolie, it averaged 15 degrees Celsius, compared to the usual 12 degrees Celsius. and 14.6°C in Gasbay, compared to 11.5°C during normal hours.
Rainfall was below normal in most areas of Quebec, except in the east. This was particularly evident in Montreal, where only 27 mm of rain was recorded, compared to the usual 83 mm of rain in September. 68% rainfall deficit.
“We must be vigilant”
Philippe Cachon, professor of hydroclimatology at the Department of Geography at the University of Quebec in Montreal (UQAM), believes that this sequence of good weather should not make us lose sight of the risks associated with climate change.
“We had the hottest summer on record in Canada,” he recalls. There is a risk that September will end with three or four consecutive months of hot temperatures, especially in the north. [que les normales]. It’s unheard of, it’s exceptional. And it seems to be happening all over the world. »
In fact, September 2023 was the hottest month ever recorded in France, Germany, Poland or Switzerland, Agence France-Presse reported on Friday.
However, heavy rainfall followed by drought is one of the expected effects of climate change, Mr. Kachon recalled.
“Right now, the North Atlantic continues to be much warmer than usual,” he notes. This means high humidity and low pressure systems will move more slowly than usual. » Result: Sudden, localized storms with heavy rainfall.
as Rain in New York on Friday flooded streets and paralyzed part of the subway system, explains Prof.
Above all, this autumn’s dry weather in Quebec is worth celebrating: the rainy summer raised the level of lakes and rivers and saturated the soil. “September allowed everything to dry out a bit,” Mr. Gachon approves. It also limited the risk of flooding. » Nevertheless, according to him, autumn has not yet begun. “We have to be vigilant. »
Effects on fall foliage?
A hot and dry autumn can, in some cases, delay the appearance of autumn colours, confirms Michael Labrecque, head of the Botanic Garden’s research department.
Temperature can also play a role, as periods of sunlight mainly shorten the cessation of photosynthetic production in trees.
“If it’s too hot, it slows down the process and the fall colors appear later,” explains the researcher. “What we’re seeing this year, especially in southern Quebec, is a little less progress than what we usually see in fall colors. »
According to the Bonjour Québec interactive map This allows you to imitate autumn colors, most areas bordering the St. Lawrence River are only at the beginning of the process until September 28. The color season lasts from September 15 to October 15.
Drought causes the leaves to fall before they change color, says Mr. Labrec. “Fortunately, we had a very wet summer,” he says. We are not in a disaster. We can all enjoy the good weather and the display of colors. »
