December weather forecast
St. Louis, MO

A beautiful twilight over the Gateway Arch in St. Louis, Missouri
A beautiful twilight over the Gateway Arch in St. Louis, Missouri

Weather in December

December, the first month of the winter in St. Louis, is still a cold month, with an average temperature varying between 27°F (-2.8°C) and 42.4°F (5.8°C).

Temperature

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

Humidity

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

Rainfall

In December, in St. Louis, the rain falls for 9.4 days. Throughout December, 2.84" (72.1mm) of precipitation is accumulated. In St. Louis, during the entire year, the rain falls for 112.6 days and collects up to 40.96" (1040.3mm) of precipitation.

Snowfall

January through April, November and December are months with snowfall in St. Louis. In St. Louis, Missouri, during December, snow falls for 3.7 days and regularly aggregates up to 4.4" (111.8mm) of snow. Throughout the year, in St. Louis, there are 14.5 snowfall days, and 17.7" (449.6mm) of snow is accumulated.

Daylight

With an average of 9h and 31min of daylight, December has the shortest days of the year in St. Louis.
On the first day of the month, sunrise is at 6:59 am and sunset at 4:40 pm. On the last day of December, in St. Louis, sunrise is at 7:18 am and sunset at 4:49 pm CST.

Sunshine

The month with the least sunshine in St. Louis is December, with an average of 4.2h of sunshine.

UV index

The months with the lowest UV index in St. Louis are January and December, with an average maximum UV index of 2. A UV Index of 2, and less, symbolizes a low threat to health from unsafe exposure to UV radiation for the average person.
Note: The daily maximum UV index of 2 in December interpret into the following advice:
Extended sun exposure is not an issue for the majority. Children, infants, and fair-skinned individuals always need to be protected. 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.
[Resources]

FAQ

What is the most humid month in St. Louis?

December is the most humid month, with an average relative humidity of 75.8%.

What is the average humidity in December in St. Louis?

In December, the average relative humidity in St. Louis is 75.8%.

How much does it rain in St. Louis in December?

In December, in St. Louis, the rain falls for 9.4 days. Throughout December, 2.84" (72.1mm) of precipitation is accumulated.

How many days does it snow in December in St. Louis?

In St. Louis, Missouri, during December, snow falls for 3.7 days and regularly aggregates up to 4.4" (111.8mm) of snow.

What is the month with the shortest days in St. Louis?

December has the shortest days of the year in St. Louis, with an average of 9h and 31min of daylight.

What is the average length of the day in December in St. Louis?

In St. Louis, Missouri, the average day length in December is 9h and 31min.

When are sunrise and sunset in December in St. Louis?

In December, on the first day of the month, sunrise is at 6:59 am and sunset at 4:40 pm. On the last day of the month, in St. Louis, sunrise is at 7:18 am and sunset at 4:49 pm CST.

What is the month with the least sunshine in St. Louis?

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

How long on average sun shines in December in St. Louis?

The average sunshine duration in December in St. Louis, Missouri, is 4.2h.

What is the month with the lowest UV index in St. Louis?

January and December, with an average maximum UV index of 2, are months with the lowest UV index in St. Louis, Missouri.

What is the UV index intensity in December in St. Louis?

The average daily maximum UV index in December in St. Louis, Missouri, is 2. A UV Index estimate of 2, and below, represents a low health risk from unsafe exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average snowfall days
Average daylight
Average sunshine
Average UV index

Average temperature in December
St. Louis, MO

Average temperature in December - St. Louis, MO
  • Average high temperature in December: 42.5°F

The warmest month (with the highest average high temperature) is July (89.1°F).
The month with the lowest average high temperature is January (39.9°F).

  • Average low temperature in December: 26.9°F

The month with the highest average low temperature is July (71°F).
The coldest month (with the lowest average low temperature) is January (23.7°F).

[Resources]

Average humidity in December
St. Louis, MO

Average humidity in December - St. Louis, MO
  • Average humidity in December: 75.8%

The month with the highest relative humidity is December (75.8%).
The month with the lowest relative humidity is April (63.5%).

[Resources]

Average rainfall in December
St. Louis, MO

Average rainfall in December - St. Louis, MO
  • Average rainfall in December: 2.8"

The wettest month (with the highest rainfall) is May (4.7").
The driest month (with the least rainfall) is February (2.2").

[Resources]

Average rainfall days in December
St. Louis, MO

Average rainfall days in December - St. Louis, MO
  • Average rainfall days in December: 9.4 days

The month with the highest number of rainy days is May (11.9 days).
The month with the least rainy days is September (7.4 days).

[Resources]

Average snowfall in December
St. Louis, MO

Average snowfall in December - St. Louis, MO
  • Average snowfall in December: 4.4"

The month with the highest snowfall is January (5.6").
The months with the least snowfall are May, June, July, August, September and October (0").

[Resources]

Average snowfall days in December
St. Louis, MO

Average snowfall days in December - St. Louis, MO
  • Average snowfall days in December: 3.7 days

The month with the highest number of snowfall days is January (4.7 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).

[Resources]

Average daylight in December /
Average sunshine in December
St. Louis, MO

Average daylight in December / Average sunshine in December - St. Louis, MO
  • Average daylight in December: 9h and 31min

The month with the longest days is June (Average daylight: 14h and 49min).
The month with the shortest days is December (Average daylight: 9h and 31min).

  • Average sunshine in December: 4h and 12min

The month with the most sunshine is July (Average sunshine: 10h and 0min).
The month with the least sunshine is December (Average sunshine: 4h and 12min).

[Resources]

Average UV index in December
St. Louis, MO

Average UV index in December - St. Louis, MO
  • Average UV index in December: 2

The months with the highest UV index are June, July and August (UV index 9).
The months with the lowest UV index are January and December (UV index 2).

[Resources]

Weather forecast for your location

1. Click Locate me button
2. Allow the app to use your location
* you will be automatically redirected to the weather forecast for your location