January 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 January

January, like December, in St. Louis is a wintry winter month, with average temperature fluctuating between 39.9°F (4.4°C) and 23.7°F (-4.6°C).

Temperature

The coldest month in St. Louis is January, with an average high-temperature of 39.9°F (4.4°C) and an average low-temperature of 23.7°F (-4.6°C).

Humidity

The average relative humidity in St. Louis is 73%.

Rainfall

In January, in St. Louis, the rain falls for 8.9 days. Throughout January, 2.4" (61mm) 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

Months with snowfall in St. Louis are January through April, November and December. The month with the most snowfall in St. Louis, Missouri, is January when snow falls for 4.7 days and typically aggregates up to 5.6" (142.2mm) of snow.

Daylight

In January, the average length of the day in St. Louis, Missouri, is 9.8h.

Sunshine

The average sunshine in St. Louis is 5.2h.

UV index

Months with the lowest UV index in St. Louis are January and December, with an average maximum UV index of 2. A UV Index value of 2, and less, symbolizes a low health risk from the exposure to the Sun's UV rays for the ordinary person.
Note: In January, the average maximum UV index of 2 translate into the following recommendations:
For the majority, extended sun exposure is not of great concern. Infants and people with sensitive skin must always be protected. The solar radiation is most powerful near the mid-day, so the exposure to the direct Sun should be reduced accordingly. On bright days sunglasses that block both UVA and UVB rays should be worn. A hat with a wide brim is extremely helpful, as it can prevent roughly 50% of UV radiation from reaching the eyes. Caution! The reflection of snow can nearly double the intensity of the Sun's UV radiation.
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FAQ

What is the coldest month in St. Louis?

January is the coldest month in St. Louis, with an average high-temperature of 39.9°F (4.4°C) and an average low-temperature of 23.7°F (-4.6°C).

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

The average relative humidity in January in St. Louis, Missouri, is 73%.

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

In St. Louis, Missouri, during January, the rain falls for 8.9 days and regularly aggregates up to 2.4" (61mm) of precipitation.

When does it snow the most in St. Louis?

January is the month with the most snowfall in St. Louis, Missouri. Snow falls for 4.7 days and accumulates 5.6" (142.2mm) of snow.

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

In St. Louis, Missouri, in January, snow falls for 4.7 days, with typically accumulated 5.6" (142.2mm) of snow.

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

In January, the average length of the day is 9.8h.

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

In St. Louis, the average sunshine in January is 5.2h.

What are the months with the lowest UV index in St. Louis?

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

How high is the UV index in January in St. Louis?

In St. Louis, Missouri, the average daily maximum UV index in January is 2. A UV Index estimate of 2, and below, represents a low health risk from the exposure to the Sun's UV rays.

Average temperature in January
St. Louis, MO

Average temperature in January - St. Louis, MO
  • Average high temperature in January: 4.4°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 January: -4.6°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 January
St. Louis, MO

Average humidity in January - St. Louis, MO
  • Average humidity in January: 73%

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 January
St. Louis, MO

Average rainfall in January - St. Louis, MO
  • Average rainfall in January: 61mm

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 January
St. Louis, MO

Average rainfall days in January - St. Louis, MO
  • Average rainfall days in January: 8.9 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 January
St. Louis, MO

Average snowfall in January - St. Louis, MO
  • Average snowfall in January: 142.2mm

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 January
St. Louis, MO

Average snowfall days in January - St. Louis, MO
  • Average snowfall days in January: 4.7 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 January /
Average sunshine in January
St. Louis, MO

Average daylight in January / Average sunshine in January - St. Louis, MO
  • Average daylight in January: 9.8h

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 January: 5.2h

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 January
St. Louis, MO

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