December weather forecast
St. Louis, MO

December in St. Louis is firmly within the winter season. Bitter cold conditions greet residents, often accompanied by snow. Temperatures plummet to their second-lowest of the year, averaging at 26.9°F (-2.8°C). As a result, the city experiences winter's first significant snowfall since the onset of the year-end season. The festive period culminates with city-wide Christmas and New Year celebrations, all under the spell of the winter magic.

Temperature

December's onset in St. Louis corresponds with a shift in the average high-temperature, moving from a moderate 55.6°F (13.1°C) in November to a cold 42.4°F (5.8°C). An average minimum temperature of 27°F (-2.8°C) is recorded in St. Louis during the month of December.

Humidity

With an average relative humidity of 75.8%, December is the most humid month in St. Louis.

Rainfall

In St. Louis, in December, it is raining for 9.4 days, with typically 2.83" (72mm) of accumulated precipitation. Throughout the year, in St. Louis, there are 112.6 rainfall days, and 40.94" (1040mm) of precipitation is accumulated.

Snowfall

January through April, November and December are months with snowfall in St. Louis. In St. Louis, in December, snow falls for 3.7 days, with typically accumulated 4.41" (112mm) of snow. In St. Louis, during the entire year, snow falls for 14.5 days and aggregates up to 17.72" (450mm) of snow.

Daylight

With an average of 9h and 30min of daylight, December has the shortest days of the year in St. Louis, Missouri.
On the first day of the month, sunrise is at 7:00 am and sunset at 4:39 pm. On the last day of December, in St. Louis, Missouri, sunrise is at 7:18 am and sunset at 4:49 pm CST.

Sunshine

With an average of 4.2h of sunshine, December has the least sunshine of the year in St. Louis, Missouri.

UV index

January and December, with an average maximum UV index of 2, are months with the lowest UV index in St. Louis. A UV Index estimate of 2, and below, represents a low threat to health from unsafe exposure to UV radiation for ordinary individuals.
Note: In December, the maximum UV index of 2 suggests this advice:
Most individuals face no major issues with lengthy exposure to the sun, but children, infants, and individuals with fair skin always require protection. Being exposed to the midday Sun can have harmful effects due to strong UV radiation; always take precautions. Consider a wide-brim hat essential for effective sun defense covering your face, neck, and eyes. Foresee this! The reflection from snow can nearly double the intensity of UV radiation from the Sun.