August Weather in Joliet, United States

Last updated: June 24, 2025

In Joliet, United States, the average temperature in August hovers around 21°C (69°F), offering a pleasant climate. However, be prepared for temperature fluctuations, with the minimum dipping to 6°C (44°F) and the maximum soaring to 37°C (99°F). During this month, the region experiences approximately 25 mm (1.0 in) of precipitation over 5 days, and the average humidity is notably high at 80%, ensuring a tropical ambiance throughout.

August Temperature in Joliet

In August in Joliet, the average temperature is 21°C (69°F). Maximum temperatures can reach up to 37°C (99°F), while minimum temperatures can drop to as low as 6°C (44°F). Be prepared for a warm climate with significant temperature fluctuations, making it ideal for both outdoor activities and comfortable evenings.

August Weather in Joliet: Daily Temperature Highs, Lows, and Averages

The chart illustrates August temperature patterns in Joliet, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Joliet, August typically has an average temperature of 21°C (69°F), with highs reaching up to 37°C (99°F) and lows dropping to around 6°C (44°F).

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

August Precipitation in Joliet

In Joliet in August, the total precipitation amount is 25 mm (1.0 in) over a span of 5 days.

August Precipitation Trends in Joliet

The chart displays monthly precipitation patterns in Joliet, with values for each month alongside August’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how August’s conditions compare to those of other months. In Joliet, August typically receives around 25 mm (1.0 inches) of precipitation spread over approximately 5 days.

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

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Millimeters (mm) Inches (in)

August Humidity in Joliet

In Joliet in August, humidity is 80%. With an average temperature of 21°C (69°F), this humidity feels like a warm, sticky embrace, making outdoor activities a bit challenging for travelers as the air becomes heavy and can lead to fatigue while sightseeing.

August Average Humidity in Joliet

This chart illustrates the average monthly humidity levels in Joliet, with August’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In August, average humidity in Joliet is approximately 80%, offering insight into how humid the weather typically is during this month.

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

August UV Index in Joliet

In Joliet in August, the maximum UV index is 9, which corresponds to a very high Exposure Category. The time to burn is just 15 minutes, so it's essential to take precautions. For detailed information, you can check the Hourly UV Index in Joliet.

Maximum UV Index Levels in Joliet for August

The chart shows the monthly maximum UV Index (UVI) for Joliet in August, 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 August, the maximum UV index in Joliet typically reaches 9, which falls under the very high exposure category.

Data source: Joliet August 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 August Weather in Joliet Compares to Other Months

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

This table compares monthly weather conditions in Joliet, showing how August’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	-4°C (25°F)	21 mm (0.8 inches)	85%	moderate
February Weather	-7°C (20°F)	46 mm (1.8 inches)	85%	moderate
March Weather	2°C (35°F)	44 mm (1.7 inches)	79%	high
April Weather	5°C (42°F)	76 mm (3.0 inches)	74%	very high
May Weather	12°C (53°F)	82 mm (3.2 inches)	76%	very high
June Weather	18°C (64°F)	76 mm (3.0 inches)	79%	extreme
July Weather	22°C (72°F)	32 mm (1.3 inches)	81%	very high
August Weather	21°C (69°F)	25 mm (1.0 inches)	80%	very high
September Weather	15°C (60°F)	57 mm (2.2 inches)	76%	very high
October Weather	6°C (43°F)	57 mm (2.2 inches)	74%	moderate
November Weather	1°C (35°F)	34 mm (1.3 inches)	81%	moderate
December Weather	-3°C (28°F)	30 mm (1.2 inches)	87%	low