Weather in Chamonix-Mont-Blanc in December

The month to avoid. December is the month most people should skip in Chamonix-Mont-Blanc. Highs sit at 3.3 °C and the day is short; this is an indoors-with-excursions month, not an outdoors-all-day one.

December ranks 11 of 12 — near the bottom of Chamonix-Mont-Blanc's year. September is the month that works, and the swing between the two is 59 points, which is a different holiday rather than a slightly better one.

Rain on 14 days, 4 of them heavy. Enough to need a plan B, not enough to need a plan around it. Layers, and a genuinely waterproof outer — at 3.3 °C the difference between a good day and a miserable one is entirely down to what you are wearing.

What the averages hide

Averages flatten a month, and this one hides a few things: 25 nights drop below freezing, so anything left outside stays frozen. Across the twenty years measured, the hottest December day reached 11.7 °C and the coldest night fell to -19.5 °C, and the wettest single day dropped 47 mm — roughly 43% of the month's rain in one day.

December is moderately variable: 3 mm in the driest year against 277 mm in the wettest, around an average of 110 mm. Roughly two Decembers in three land near that average, and the third does something else entirely.

Wind is light at 3.4 km/h, so the temperature on the page is close to the temperature on your skin, and humidity runs at 84%, which at 3.3 °C means damp rather than muggy — the kind of cold that gets into a coat and stays there.

How December sits in the year

Temperatures hold steady either side: 8 °C in November, 3.3 here, 1.8 in January. Nothing about the timing within the month matters much.

Daylight in December

December sits at the dark end of Chamonix-Mont-Blanc's year — 8.7 hours of daylight against 15.7 at midsummer, holding steady all month. Sightseeing days are genuinely shorter, and an itinerary built for summer will not fit.

An inland climate

With no coast nearby, the year swings a fair way — 28.9 °C between the warmest afternoons and the coldest nights, wider than any coastal city at this latitude would manage. At 1060 m the air is thin enough to matter — sun that burns faster than the temperature suggests, and nights that cool off quickly.

How busy it gets

Off season. The genuine off season: cheapest by a distance, with the caveat that some tours and restaurants close entirely.

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

December in Chamonix-Mont-Blanc versus nearby

If Chamonix-Mont-Blanc is one option among several, the nearby comparison is worth making. Annecy is a better bet in December — 3.1 °C warmer, 1 day less rain. Zermatt is close enough to be a coin toss — 3.6 °C cooler, 1 day less rain.

So: December is a compromise. September is 58 points better and is what Chamonix-Mont-Blanc is actually like at its best — worth moving the trip for if that is possible, and worth adjusting expectations for if it is not.

Every month in Chamonix-Mont-Blanc

See all twelve months in Chamonix-Mont-Blanc, or where else to go in December.