St. Charles (MO) Weather & Climate: Best Time to Visit
Average temperatures, rainfall, sunshine and the best time to visit St. Charles.
Climate overview of St. Charles
St. Charles, Missouri, United States of America, experiences significant temperature variation throughout the year. Summers bring daytime highs of 31°C (88°F) in July, while winters cool to 5°C (41°F) in January.
Rain/snowfall is high, totalling around 1114 mm (44 in) per year. April is the wettest month and January the driest. The sunniest month is July, with 10.4 hours of sunshine per day on average.
St. Charles Weather by Month
Pick a month to see the average temperature, rainfall and sunshine in St. Charles — and find the best time to visit.
Monthly Temperature in St. Charles
Depending on the time of the year, temperatures range from very warm to chilly in St. Charles. Average maximum daytime temperatures range from a very warm 31°C (88°F) in July, the warmest time of the year, to a chilly 5°C (41°F) during cooler months like January.
At night, you can expect temperatures ranging from 20°C (68°F) in July to around -6°C (21°F) during January.
Check out our detailed temperature page for more information.
Temperature ranges by month
Rainfall in St. Charles
St. Charles has a relatively rain/snowy climate with high precipitation levels, averaging 1114 mm (44 in) of rain/snowfall annually. Significant seasonal changes in precipitation occur throughout the year. In the wettest month, April it receives high rainfall, averaging 128 mm (5 in) of precipitation, recorded across 11 rainy days. In contrast, the driest month January brings less snow/rainfall, with 45 mm (1.8 in) over 7 snowy/rainy days. For more details, please visit our St. Charles Precipitation page.
The mean monthly precipitation over the year, including rain, hail, and snow
The average number of days each month with precipitation
Sunshine Hours in St. Charles
Seasonal changes in sunshine hours are quite dramatic in St. Charles. While July receives considerable daily sunshine with up to 10.4 hours, December marks the darkest time of the year, where sunshine is scarce with only 4.3 hours of sunlight per day.
Visit our detailed sunshine hours page for more information.
Monthly hours of sunshine
Daily hours of sunshine
Daily percentage of sunshine
Humidity in St. Charles by Month
The relative humidity is high throughout the year in St. Charles.
The city experiences its highest humidity in December, reaching 74%. In April, the humidity drops to its lowest level at 63%. What does this mean? Read our detailed page on humidity levels for further details.
Relative humidity over the year
Best Time to Visit St. Charles
Rainfall during this time ranges from 80 mm (3.1 in) in October to 128 mm (5 in) in April. This means you can expect a mix of sunny days and occasional showers. Looking for inspiration on where to travel this year? We have a tool that recommends destinations based on your ideal conditions. Find out where to go with our weather planner.
Frequently asked questions about the climate in St. Charles
What is the best time to visit St. Charles?
September and October typically offer the most optimal weather in St. Charles. In contrast, January, February and December tend to have less optimal conditions.
What temperatures can I expect in St. Charles?
Daytime highs range from 5°C (41°F) in January to 31°C (88°F) in July. Nighttime lows range from -6°C (21°F) to 20°C (68°F). Temperatures vary considerably through the year.
How much rain does St. Charles get?
Annual rainfall is around 1114 mm (44 in). April is the wettest month with 128 mm (5 in), while January is the driest with 45 mm (1.8 in).
How sunny is St. Charles?
St. Charles receives around 2,594 hours of sunshine per year. July is the sunniest month with 311 hours, while December is the cloudiest with just 128 hours. Overall, St. Charles enjoys abundant sunshine.
St. Charles 3-Day Forecast
St. Charles (MO) 3-Day Forecast
St. Charles on the map
St. Charles is highlighted — select any city to see its climate.
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