December weather forecast
St. Louis, MO

The first month of the winter, December, is also a wintry month in St. Louis, with temperature in the range of an average high of 42.4°F (5.8°C) and an average low of 27°F (-2.8°C).

Temperature

In December, the average high-temperature in St. Louis drops from a mild 55.6°F (13.1°C) in November to a wintry 42.4°F (5.8°C). In December, in St. Louis, the average low-temperature is 27°F (-2.8°C).

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

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

Daylight

The month with the shortest days in St. Louis is December, with an average of 9h and 31min of daylight.
On the first day of December in St. Louis, Missouri, sunrise is at 6:59 am and sunset at 4:40 pm. On the last day of the month, 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

The months with the lowest UV index in St. Louis, Missouri, are January and December, with an average maximum UV index of 2. A UV Index estimate of 2, and below, represents a low threat to health from unprotected exposure to Sun's UV rays for the ordinary person.
Note: The daily maximum UV index of 2 in December interpret into the following advice:
People with sensitive skin, children, and babies should always be protected from prolonged sun exposure. The Sun's most intense and consequently most harmful UV radiation during midday hours should be decreased by minimizing exposure and seeking shade. A wide-brim hat offers excellent sun protection for the eyes, ears, face, and neck. Sunglasses with UVA and UVB protection significantly reduce eye damage from sun exposure. Tightly woven, loose-fitting clothes provide additional protection from the Sun. Caution! The reflection of snow can nearly double the intensity of the Sun's UV radiation.