Weather in Québec in September

A good month. September is a solid month to be in Québec. Highs average 19.6 °C, lows 10.2 °C, and rain falls on 14 days — nothing in the month is working against you.

September is the highest-scoring month of the twelve. The nearest rival is August, and the month at the other end of the year is December.

Rain on 14 days, 3 of them heavy. Enough to need a plan B, not enough to need a plan around it. Nothing specialised needed — this is the month you pack for the trip rather than for the weather.

What the averages hide

Averages flatten a month, and this one hides a few things: it never really gets hot: not one day in an average September reaches 30 °C. Across the twenty years measured, the hottest September day reached 29.5 °C and the coldest night fell to -0.1 °C, and the wettest single day dropped 68 mm — roughly 62% of the month's rain in one day.

September is statistically steady but not small: the year-to-year variation is modest in relative terms, yet the wettest September on record still delivered 211 mm against 73 mm in the driest. In a month this wet, even a tame spread is a lot of rain in absolute terms — the 109 mm average is a reasonable planning figure, not a promise.

Wind is light at 4 km/h, so the temperature on the page is close to the temperature on your skin, and humidity runs at 84%, high enough to notice on the warm days without dominating them.

How September sits in the year

The month is on the way down: 3.7 °C cooler than August, with October dropping another 7.9 °C. The first week and the last are not the same trip.

Daylight in September

12.6 hours of daylight, losing 1.6 hours across the month. That is between Québec's extremes of 15.8 and 8.6 hours, so days are long enough not to constrain the plan.

An inland climate

Québec has no sea to moderate it, and it shows: 41.3 °C separates the hottest afternoon of the year from the coldest night. That is a genuinely continental range, and it means summer and winter here are barely the same place.

How busy it gets

Peak season. Expect the highest prices of the year and to be booking well ahead.

Crowd levels are estimated from climate desirability and school-holiday calendars, not from visitor numbers.

September in Québec versus nearby

If Québec is one option among several, the nearby comparison is worth making. Sherbrooke is close enough to be a coin toss — within a degree on temperature, the same number of rain days. Saguenay is close enough to be a coin toss — within a degree on temperature, 1 day less rain.

So: September is the answer for Québec. If it is booked out or priced out, August is the next best thing at 2 points behind, and December is the month to keep off the shortlist.

Every month in Québec

See all twelve months in Québec, or where else to go in September.