March Weather in St. Charles, United States

Last updated: June 24, 2025

In March, the average temperature in St. Charles, United States is a cool 9°C (48°F). Temperatures can fluctuate widely, with minimums dipping as low as -4°C (25°F) and maximums reaching up to 28°C (83°F). Expect 77 mm (3.0 in) of precipitation spread over 9 days, contributing to a relatively high average humidity of 83%.

March Temperature in St. Charles

In March in St. Charles, the average temperature is 9°C (48°F). Maximums can reach 28°C (83°F) and minimums can be as low as -4°C (25°F). Be prepared for a wide range of temperatures when planning your trip!

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

The chart illustrates March 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, March typically has an average temperature of 9°C (48°F), with highs reaching up to 28°C (83°F) and lows dropping to around -4°C (25°F).

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

March Precipitation in St. Charles

In St. Charles in March, the precipitation amount is 77 mm (3.0 in) over the course of 9 days.

March Precipitation Trends in St. Charles

The chart displays monthly precipitation patterns in St. Charles, with values for each month alongside March’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how March’s conditions compare to those of other months. In St. Charles, March typically receives around 77 mm (3.0 inches) of precipitation spread over approximately 9 days.

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

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Millimeters (mm) Inches (in)

March Humidity in St. Charles

In St. Charles in March humidity is 83%. With an average temperature of 9°C (48°F), this humidity feels like an enveloping blanket, making outdoor activities quite uncomfortable and encouraging travelers to seek shelter or shade frequently.

March Average Humidity in St. Charles

This chart illustrates the average monthly humidity levels in St. Charles, with March’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In March, average humidity in St. Charles is approximately 83%, offering insight into how humid the weather typically is during this month.

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

March UV Index in St. Charles

In St. Charles in March, the maximum UV index is 7, which corresponds to the high Exposure Category. This means that the time to burn is approximately 25 minutes. For more detailed information, you can check the Hourly UV Index in St. Charles.

Maximum UV Index Levels in St. Charles for March

The chart shows the monthly maximum UV Index (UVI) for St. Charles in March, 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 March, the maximum UV index in St. Charles typically reaches 7, which falls under the high exposure category.

Data source: St. Charles March 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 March 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 March’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 March’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