January weather forecast
St. Louis, MO

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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 in St. Louis begins the year firmly within the grips of the winter season. Freezing conditions are predominant, with the lowest mean temperature of 23.7°F (-4.6°C). Winterscape often includes snowfall totaling 5.6" (142mm) across the city. The onset of the year also carries shorter days, with sunlight barely stretching beyond mid-afternoon. The pervading chill in the air set the stage for a period of relative tranquility in terms of rain.

Temperature

In St. Louis, Missouri, the lowest average temperatures are observed in January, with a high of 39.9°F (4.4°C) and a low of 23.7°F (-4.6°C).

Humidity

In January, 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. 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. The month with the most snowfall in St. Louis is January, when snow falls for 4.7 days and typically aggregates up to 5.59" (142mm) of snow.

Daylight

The average length of the day in January in St. Louis, Missouri, is 9h and 50min.
On the first day of the month, sunrise is at 7:18 am and sunset at 4:49 pm. On the last day of January, in St. Louis, sunrise is at 7:07 am and sunset at 5:20 pm CST.

Sunshine

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

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 minimal health hazard from exposure to the Sun's UV radiation for the ordinary person.
Note: The maximum UV index of 2 during January leads to these instructions:
Protection from prolonged sun exposure is necessary for babies, children, and individuals with sensitive skin. Avoiding the Sun's peak radiation during midday hours is essential for health and safety. Loose clothes with a tight weave are optimal for safeguarding yourself against the Sun's rays. Remember to consider! The UV radiation from the Sun can be intensified nearly twice by the reflection of snow.

Frequently asked questions

What part of the year is the coldest?

The coldest temperatures occur during January, when averages reach a peak of 39.9°F (4.4°C) and a low of 23.7°F (-4.6°C).

How cold is January?

An average high-temperature, in January, in St. Louis, is 39.9°F (4.4°C) and the average low-temperature is 23.7°F (-4.6°C).

What is the average humidity in January?

The average relative humidity in January is 73%.

How many days does it rain in January?

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

What is the snowiest month?

January is the month with the most snowfall. Snow falls for 4.7 days and accumulates 5.59" (142mm) of snow.

How many days does it snow in January?

In January, it is snowing for 4.7 days. Throughout January, 5.59" (142mm) of snow is accumulated.

What is the average length of the day in January?

In St. Louis, the average day length in January is 9h and 50min.

When is the sunrise / sunset in January?

On the first day of January, sunrise is at 7:18 am and sunset at 4:49 pm. On the last day of the month, sunrise is at 7:07 am and sunset at 5:20 pm CST.

How long on average sun shines in January?

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

What are the months with the lowest UV index?

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 January in St. Louis?

In January, the average daily maximum UV index is 2. A UV Index estimate of 2, and below, represents a low health risk from exposure to the Sun's UV radiation.
Average humidity
Average rainfall days
Average snowfall days
Average daylight
Average sunshine
Average UV index

Average temperature in January
St. Louis, MO

Average temperature in January - St. Louis, MO
  • Average high temperature in January: 39.9°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 January: 23.7°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).

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%).

Average rainfall in January
St. Louis, MO

Average rainfall in January - St. Louis, MO
  • Average rainfall in January: 2.4"

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

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).

Average snowfall in January
St. Louis, MO

Average snowfall in January - St. Louis, MO
  • Average snowfall in January: 5.6"

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").

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

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: 9h and 5min

The month with the longest days is June (Average daylight: 14h and 48min).
The month with the shortest days is December (Average daylight: 9h and 30min).

  • Average sunshine in January: 5h and 1min

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).

Average UV index in January
St. Louis, MO

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

St. Louis, Missouri, USA

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