Weather in Chamonix-Mont-Blanc in October

Shoulder season. October is shoulder season in Chamonix-Mont-Blanc — cheaper, quieter, and a genuine gamble. Highs sit at 14.9 °C and the day is short; this is an indoors-with-excursions month, not an outdoors-all-day one.

October ranks 5 of 12 in Chamonix-Mont-Blanc: past the worst of the year but short of September, which is the month to book if the dates are open.

Rain on 12 days, 3 of them heavy. Enough to need a plan B, not enough to need a plan around it. Layers, and a genuinely waterproof outer — at 14.9 °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: 3 nights fall below freezing. Across the twenty years measured, the hottest October day reached 25.1 °C and the coldest night fell to -5.7 °C, and the wettest single day dropped 35 mm — roughly 41% of the month's rain in one day.

October is moderately variable: 26 mm in the driest year against 179 mm in the wettest, around an average of 86 mm. Roughly two Octobers in three land near that average, and the third does something else entirely.

Wind is light at 2.8 km/h, so the temperature on the page is close to the temperature on your skin, and humidity runs at 78%, which at 14.9 °C means damp rather than muggy — the kind of cold that gets into a coat and stays there.

How October sits in the year

The month is on the way down: 3.9 °C cooler than September, with November dropping another 6.9 °C. The first week and the last are not the same trip.

Daylight in October

11 hours of daylight, losing 1.6 hours across the month. That is between Chamonix-Mont-Blanc'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 — 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

Busy. Popular without being frantic; book the things you care about, improvise the rest.

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

October 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 October — 3.1 °C warmer, the same number of rain days. Zermatt is the weaker option in October — 4 °C cooler, 1 day more rain.

So: October works, with September the better month by 13 points if the dates can move. If they cannot, nothing here should stop you booking.

Every month in Chamonix-Mont-Blanc

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