The dark side of fall is coming this week

The shadow

The sun is less present during the fall for several reasons. First there is the tilt of the Earth, of course. The days are shorter. During the month of October, we lose on average around three minutes of sunshine each day. That’s over an hour and a half for the entire month. We also lose more than an hour during the month of November. There are several ways to measure the length of a day, but we can still say that between September 1 and November 30, we lose more than four hours of sunlight.

The nights are long

Then there are the clouds, much more present in November than at the beginning of autumn. The difference is striking between the September and November averages. In Montreal, in particular, the average sunshine for the month of September is 182 hours. In November, this figure drops to 84 hours. Although the days are 25% shorter, the gap remains immense. We see less than 50% of the Sun in November, compared to September. The year 2024 has spoiled us in this regard. We were treated to 248 hours of sunshine in September, 35% more than the average of 182 hours. In October, we were treated to 181 hours of sunshine, an increase of more than 25% on the average of 144 hours. And November has already exceeded the average for the entire month, with 89 hours as of November 19.

Return of the clouds

Unfortunately, the situation is about to change. The clouds will impose their law over the next few days. And their reign could last almost until the end of the month. From Thursday, gray weather will settle in over almost the entire province. There will be precipitation in southern Quebec as well as in the east.

The situation will not be much better to start the weekend. Temperatures will drop, and rain will change to snow in many areas. Bas-Saint-Laurent, Gaspésie, Côte-Nord, Saguenay and Abitibi-Témiscamingue should see snowflakes, or even small broadsides in places.

Absent sun

The sun will take leave for several days. The only small sunny window could be next Monday, and even then it will be around normal for a November day, around three hours at best. Note that the maximum possible during this period is around nine o’clock. We will definitely be well below this mark over the next seven days.

Blanket

There is a good side to cloud cover: it serves as a blanket. According to meteorologist Bertin Ossonon, “during the night, we can lose a lot of heat if the sky is clear. This is called radiative cooling. The presence of clouds reduces this effect and offers milder temperatures, particularly at night. » Temperatures will indeed be slightly above seasonal averages over the next few days.

With the collaboration of Bertin Ossonon, meteorologist.

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