December weather forecast and climate
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 also a wintry month, with average temperature ranging between min 27°F (-2.8°C) and max 42.4°F (5.8°C).

Temperature

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

Humidity

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

Rainfall

In St. Louis, Missouri,, it is raining for 9.4 days, with typically 2.84" (72.1mm) of accumulated precipitation. 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

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

Daylight

The month with the shortest days in St. Louis is December, with an average of 9.5h of daylight.

Sunshine

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

UV index

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 of 2, and less, symbolizes a minimal health hazard from the exposure to the Sun's UV rays for average individuals.
Note: The average daily UV index of 2 transform into the following instructions:
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. Sun-protective clothing, a long-sleeved shirt and pants, a wide-brimmed hat, and UVA and UVB-blocking sunglasses are particularly helpful in blocking UV radiation's harmful effects. Beware! The strength of the UV rays is increased nearly double-fold by the reflection of the snow.
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FAQ

What is the most humid month in St. Louis?

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

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

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

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

In St. Louis, Missouri, in December, it is raining for 9.4 days, with typically 2.84" (72.1mm) of accumulated precipitation.

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

In December, in St. Louis, it is snowing for 3.7 days. Throughout December, 4.4" (111.8mm) of snow is accumulated.

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

The month with the shortest days is December, with an average of 9.5h of daylight.

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

In December, the average length of the day is 9.5h.

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.

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

In December, the average sunshine in St. Louis is 4.2h.

When is 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.

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

In St. Louis, Missouri, the average daily maximum UV index in December is 2. A UV Index of 2, and less, symbolizes a minimal hazard to health from unsafe exposure to the Sun's UV rays.

Average temperature in December
St. Louis, MO

Average temperature in December - St. Louis, MO
  • Average high temperature in December: 5.8°C

The warmest month (with the highest average high temperature) is July (31.7°C).
The month with the lowest average high temperature is January (4.4°C).

  • Average low temperature in December: -2.8°C

The month with the highest average low temperature is July (21.7°C).
The coldest month (with the lowest average low temperature) is January (-4.6°C).

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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%).

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Average rainfall in December
St. Louis, MO

Average rainfall in December - St. Louis, MO
  • Average rainfall in December: 72.1mm

The wettest month (with the highest rainfall) is May (119.9mm).
The driest month (with the least rainfall) is February (56.9mm).

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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).

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Average snowfall in December
St. Louis, MO

Average snowfall in December - St. Louis, MO
  • Average snowfall in December: 111.8mm

The month with the highest snowfall is January (142.2mm).
Months with the least snowfall are May, June, July, August, September and October (0mm).

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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).
Months with the least snowfall days are May, June, July, August, September and October (0 days).

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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: 9.5h

The month with the longest days is June (Average daylight: 14.8h).
The month with the shortest days is December (Average daylight: 9.5h).

  • Average sunshine in December: 4.2h

The month with the most sunshine is July (Average sunshine: 10h).
The month with the least sunshine is December (Average sunshine: 4.2h).

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Average UV index in December
St. Louis, MO

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

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

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