January Weather in St. Charles, United States

Last updated: June 24, 2025

In January, the average temperature in St. Charles, United States hovers around 4°C (39°F). Expect a minimum chill of -14°C (7°F) and the possibility of reaching a maximum warmth of 21°C (69°F). The month brings about 62 mm (2.4 in) of precipitation over 7 days, with an average humidity level of 84%.

January Temperature in St. Charles

In January in St. Charles, the average temperature is 4°C (39°F). The maximum can reach 21°C (69°F) and the minimum can be as low as -14°C (7°F). Be prepared for a wide range of temperatures, ensuring you pack layers for your travels.

January Weather in St. Charles: Daily Temperature Highs, Lows, and Averages

The chart illustrates January temperature patterns in St. Charles, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In St. Charles, January typically has an average temperature of 4°C (39°F), with highs reaching up to 21°C (69°F) and lows dropping to around -14°C (7°F).

Data source: Temperature data for St. Charles generated using information from the Copernicus Climate Change Service.

January Precipitation in St. Charles

In St. Charles in January, the total precipitation amount is 62 mm (2.4 in) observed over a span of 7 days.

January Precipitation Trends in St. Charles

The chart displays monthly precipitation patterns in St. Charles, with values for each month alongside January’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how January’s conditions compare to those of other months. In St. Charles, January typically receives around 62 mm (2.4 inches) of precipitation spread over approximately 7 days.

Data source: Precipitation data for January generated using information from the Copernicus Climate Change Service.

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Millimeters (mm) Inches (in)

January Humidity in St. Charles

In St. Charles in January, humidity is 84%. With an average temperature of 4°C (39°F), this humidity feels like a damp chill that seeps into your bones, making outdoor excursions uncomfortable and demanding more layers than you anticipate while traveling.

January Average Humidity in St. Charles

This chart illustrates the average monthly humidity levels in St. Charles, with January’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In January, average humidity in St. Charles is approximately 84%, offering insight into how humid the weather typically is during this month.

Data source: Humidity data for January generated using information from the Copernicus Climate Change Service.

January UV Index in St. Charles

In St. Charles in January, the maximum UV index is 3, which corresponds to a moderate Exposure Category. The time to burn is approximately 30 minutes. For more details on the hourly UV index in St. Charles, you can check the information here.

Maximum UV Index Levels in St. Charles for January

The chart shows the monthly maximum UV Index (UVI) for St. Charles in January, representing the highest UV radiation level. The UVI measures the intensity of ultraviolet radiation from the sun, indicating the potential risk of sunburn and UV-related health issues. In January, the maximum UV index in St. Charles typically reaches 3, which falls under the moderate exposure category.

Data source: St. Charles January UVI data generated using information from the Copernicus Climate Change Service.

UV Risk Categories

Extreme (11+): Avoid the sun, stay in shade.
Very High (8-10): Limit sun exposure.
High (6-7): Use SPF 30+ and protective clothing.
Moderate (3-5): Midday shade recommended.
Low (0-2): No protection needed.

How January Weather in St. Charles Compares to Other Months

Weather in St. Charles varies notably across the year, with each month offering distinct climate conditions. This page compares January’s weather to other months in St. Charles, focusing on differences in temperature, rainfall, humidity, and UV levels.

This table compares monthly weather conditions in St. Charles, showing how January’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	4°C (39°F)	62 mm (2.4 inches)	84%	moderate
February Weather	6°C (42°F)	93 mm (3.7 inches)	83%	moderate
March Weather	9°C (48°F)	77 mm (3.0 inches)	83%	high
April Weather	14°C (58°F)	99 mm (3.9 inches)	81%	very high
May Weather	19°C (67°F)	118 mm (4.6 inches)	78%	very high
June Weather	24°C (76°F)	106 mm (4.2 inches)	79%	very high
July Weather	27°C (81°F)	122 mm (4.8 inches)	74%	very high
August Weather	26°C (79°F)	151 mm (5.9 inches)	72%	very high
September Weather	23°C (73°F)	91 mm (3.6 inches)	75%	very high
October Weather	17°C (64°F)	108 mm (4.2 inches)	81%	high
November Weather	9°C (49°F)	78 mm (3.1 inches)	85%	moderate
December Weather	6°C (43°F)	86 mm (3.4 inches)	84%	moderate