The climate of Chamonix is moderately continental, characterized by cold winters, with temperatures often below freezing (0 °C or 32 °F), and mild or pleasantly warm summers.
Chamonix-Mont-Blanc is located in a valley at 1,000 meters (3,300 feet) above sea level, on the north-western slope of the Alps, in Haute-Savoie.
The average temperature of the coldest month (January) is of -2.2 °C (28 °F), that of the warmest month (July) is of 16.5 °C (62 °F). Here are the average temperatures.
Chamonix - Average temperatures
Min (°C)-7-6-30589962-2-6
Max (°C)3591318212423191573
Min (°F)192127324146484843362821
Max (°F)374148556470757366594537

Precipitation amounts to 1,280 millimeters (50.4 inches) per year. It ranges from 85 mm (3.3 in) in the driest months (February, March) to 130 mm (5.1 in) in the wettest (June). The summer is the rainiest season due to afternoon thunderstorms. Here is the average precipitation.
Chamonix - Average precipitation

On average, there are around 1,990 sunshine hours per year. Here are the average sunshine hours per day.
Chamonix - Sunshine


Best Time

The best time to visit Chamonix runs from June to August, since it is the mildest and sunniest period of the year. Sometimes, nights can be cool or even cold even in these months, so it can be useful to bring a sweatshirt or sweater and a jacket for the evening.