Mammoth Lakes Weather in December

The climate in Mammoth Lakes during December can be summarized as cold and damp.

December is in the winter in Mammoth Lakes and is typically the 2nd coldest month of the year. Daytime maximum temperatures average around a freezing 4°C (40°F), whilst at night -9°C (16°F) is normal.

On average December is the 2nd wettest month of the year in Mammoth Lakes with around 119mm 4.7 inches of rain making it a damp time to visit. This rainfall is typically spread over 6 days, although this may vary considerably.

On the flip side this corresponds to an average of 6.6 hours of sunshine per day.

The data used in these monthly averages covers a period of over 100 years right up until last year. As such they are a valid prediction of what to expect for the weather in Mammoth Lakes in December 2025.