July Weather in St. Charles, United States

Last updated: June 24, 2025

In July, the average temperature in St. Charles, United States is a warm 27°C (81°F), with a comfortable minimum of 18°C (64°F) and a sizzling maximum reaching up to 38°C (100°F). Expect 122 mm (4.8 in) of precipitation spread over 12 days, contributing to an average humidity of 74%. Enjoy the blend of warmth and occasional showers!

July Temperature in St. Charles

In July in St. Charles, the average temperature is 27°C (81°F), with maximums reaching up to 38°C (100°F) and minimums dipping as low as 18°C (64°F). This climate makes St. Charles an ideal destination for travelers seeking warm weather and outdoor activities during this time.

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

The chart illustrates July 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, July typically has an average temperature of 27°C (81°F), with highs reaching up to 38°C (100°F) and lows dropping to around 18°C (64°F).

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

July Precipitation in St. Charles

In St. Charles in July, the precipitation amount is 122 mm (4.8 in) over a span of 12 days.

July Precipitation Trends in St. Charles

The chart displays monthly precipitation patterns in St. Charles, with values for each month alongside July’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how July’s conditions compare to those of other months. In St. Charles, July typically receives around 122 mm (4.8 inches) of precipitation spread over approximately 12 days.

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

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Millimeters (mm) Inches (in)

July Humidity in St. Charles

In St. Charles in July humidity is 74%. With an average temperature of 27°C (81°F), this humidity feels like a warm, enveloping blanket, making traveling feel both sticky and draining, yet the heat invites you to seek out refreshing dips in pools or shady spots to relax.

July Average Humidity in St. Charles

This chart illustrates the average monthly humidity levels in St. Charles, with July’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In July, average humidity in St. Charles is approximately 74%, offering insight into how humid the weather typically is during this month.

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

July UV Index in St. Charles

In St. Charles in July, the maximum UV index reaches 10, which corresponds to a very high Exposure Category. With a time to burn of just 15 minutes, it's crucial to take precautions. For more detailed information, you can check the Hourly UV Index in St. Charles.

Maximum UV Index Levels in St. Charles for July

The chart shows the monthly maximum UV Index (UVI) for St. Charles in July, 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 July, the maximum UV index in St. Charles typically reaches 10, which falls under the very high exposure category.

Data source: St. Charles July 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 July 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 July’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 July’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