Weather in Annecy in September

Prime time. If you get to pick your dates, September is the one. Highs average 22.1 °C, lows 12.3 °C, and rain falls on 11 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 January.

Rain on 11 days, 2 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 32 °C and the coldest night fell to 3.3 °C, and the wettest single day dropped 43 mm — roughly 57% 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 161 mm against 37 mm in the driest. In a month this wet, even a tame spread is a lot of rain in absolute terms — the 76 mm average is a reasonable planning figure, not a promise.

Wind is light at 5.2 km/h, so the temperature on the page is close to the temperature on your skin, and humidity is unremarkable at 72%.

How September sits in the year

The month is on the way down: 3.8 °C cooler than August, with October dropping another 4.1 °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 Annecy's extremes of 15.7 and 8.7 hours, so days are long enough not to constrain the plan.

An inland climate

With no coast nearby, the year swings a fair way — 27.3 °C between the warmest afternoons and the coldest nights, wider than any coastal city at this latitude would manage.

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 Annecy versus nearby

If Annecy is one option among several, the nearby comparison is worth making. Chamonix-Mont-Blanc is close enough to be a coin toss — 3.3 °C cooler, 2 days more rain. Lyon is close enough to be a coin toss — within a degree on temperature, 3 days less rain.

So: September is the answer for Annecy. If it is booked out or priced out, August is the next best thing at 5 points behind, and January is the month to keep off the shortlist.

Every month in Annecy

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