Chicago

Illinois Weather in August

Average temperatures, rainfall, sunshine and the best places to visit in Illinois, the United States of America in August.

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Chicago Schaumburg Rosemont Joliet

Planning a trip to Illinois, the United States of America this August? Here's what you need to know about the weather:

What to Expect in Illinois in August

Illinois, the United States of America is a region in the United States of America. August in Illinois generally has temperatures that range from warm to very warm, with precipitation levels ranging from moderate to high. August falls during the summer season.

Temperatures

The average maximum daytime temperatures vary from warm in Roscoe at 24°C (75°F) to very warm in Metropolis at 31°C (88°F). Nighttime temperatures generally drop to 20°C (68°F) in Metropolis and 12°C (54°F) in Roscoe.

For a closer look at conditions across Illinois, the United States of America, refer to the map below.

Precipitation

In August, precipitation varies across different areas. From moderate rainfall in Tuscola with an average of 63 mm (2.5 in) to high rainfall in Monee with 138 mm (5.4 in).

Average sunshine

Plenty of sunshine can be expected in numerous places in August. Chicago typically receives 280 hours of sunlight, making it ideal for those seeking sunny weather.

Explore Illinois by month

Pick a month to see the average temperature, rainfall and sunshine in Illinois — and find the best time to visit. (based on Chicago)

January-1°C (30°F) February0°C (32°F) March8°C (46°F) April15°C (59°F) May21°C (70°F) June26°C (79°F) This monthJuly29°C (84°F) August28°C (82°F) September24°C (75°F) October17°C (63°F) November9°C (48°F) December3°C (37°F)
Best Time to Visit Illinois →

Best Places to Visit in Illinois in August

Click on a destination dot for more details. Toggle the map to compare temperatures or precipitation across Illinois.

Conditions Temperatures Precipitation
perfect weather
pleasant
tolerable
unpleasant
poor

Perfect weather is subjective. On this map perfect weather has been defined with temperatures between 20°C (68°F) and 29°C (84°F) and not too much precipitation (less than 90 mm (3.5 in) a month).

Popular Destinations in Illinois

What is the weather like in August for some of the most popular destinations in Illinois, the United States of America?

Temperature range in Illinois (August)

Precipitation variation in Illinois (August)

Chicago

In August Chicago generally has high temperatures with maximum daytime temperatures around 28°C (82°F), minimum nighttime temperatures around 18°C (64°F) and high monthly rainfall. So on average the conditions are pleasant that month.

« July
August
September »
July
August
September
Max temperature
29°C (84°F)
28°C (82°F)
24°C (75°F)
Min temperature
19°C (66°F)
18°C (64°F)
14°C (57°F)
Monthly sun hours
319 hours
280 hours
226 hours
Monthly rainfall
115 mm (4.5 in)
115 mm (4.5 in)
95 mm (3.7 in)
Monthly rainy days
11 days
11 days
9 days
Weather conditions
pleasant
pleasant
perfect
Climate in Chicago →

Schaumburg

In August Schaumburg generally has high temperatures with maximum daytime temperatures around 28°C (82°F), minimum nighttime temperatures around 17°C (63°F) and high monthly rainfall. So on average the conditions are pleasant that month.

« July
August
September »
July
August
September
Max temperature
29°C (84°F)
28°C (82°F)
24°C (75°F)
Min temperature
17°C (63°F)
17°C (63°F)
12°C (54°F)
Monthly sun hours
319 hours
280 hours
226 hours
Monthly rainfall
116 mm (4.6 in)
121 mm (4.8 in)
100 mm (3.9 in)
Monthly rainy days
11 days
11 days
9 days
Weather conditions
pleasant
pleasant
pleasant
Climate in Schaumburg →

Rosemont

In August Rosemont generally has high temperatures with maximum daytime temperatures around 28°C (82°F), minimum nighttime temperatures around 18°C (64°F) and high monthly rainfall. So on average the conditions are pleasant that month.

« July
August
September »
July
August
September
Max temperature
29°C (84°F)
28°C (82°F)
24°C (75°F)
Min temperature
19°C (66°F)
18°C (64°F)
14°C (57°F)
Monthly sun hours
319 hours
280 hours
226 hours
Monthly rainfall
116 mm (4.6 in)
115 mm (4.5 in)
96 mm (3.8 in)
Monthly rainy days
11 days
11 days
9 days
Weather conditions
pleasant
pleasant
perfect
Climate in Rosemont →

Joliet

In August Joliet generally has high temperatures with maximum daytime temperatures around 28°C (82°F), minimum nighttime temperatures around 17°C (63°F) and high monthly rainfall. So on average the conditions are pleasant that month.

« July
August
September »
July
August
September
Max temperature
29°C (84°F)
28°C (82°F)
25°C (77°F)
Min temperature
18°C (64°F)
17°C (63°F)
13°C (55°F)
Monthly sun hours
319 hours
280 hours
226 hours
Monthly rainfall
116 mm (4.6 in)
131 mm (5.2 in)
94 mm (3.7 in)
Monthly rainy days
12 days
12 days
10 days
Weather conditions
pleasant
pleasant
perfect
Climate in Joliet →

Naperville

In August Naperville generally has high temperatures with maximum daytime temperatures around 28°C (82°F), minimum nighttime temperatures around 17°C (63°F) and high monthly rainfall. So on average the conditions are pleasant that month.

« July
August
September »
July
August
September
Max temperature
29°C (84°F)
28°C (82°F)
25°C (77°F)
Min temperature
17°C (63°F)
17°C (63°F)
12°C (54°F)
Monthly sun hours
319 hours
280 hours
226 hours
Monthly rainfall
106 mm (4.2 in)
112 mm (4.4 in)
87 mm (3.4 in)
Monthly rainy days
11 days
11 days
9 days
Weather conditions
pleasant
pleasant
perfect
Climate in Naperville →

Is your destination not in the list? Have a look at all destinations in Illinois, in the United States of America.

Popular cities in August

Day & night temperatures, rainfall and average weather in Illinois in August.

City Weather Day temp Night temp Rainfall
Chicago 28°C (82°F) 18°C (64°F) 115 mm (4.5 in)
Schaumburg 28°C (82°F) 17°C (63°F) 121 mm (4.8 in)
Rosemont 28°C (82°F) 18°C (64°F) 115 mm (4.5 in)
Joliet 28°C (82°F) 17°C (63°F) 131 mm (5.2 in)
Naperville 28°C (82°F) 17°C (63°F) 112 mm (4.4 in)
Waukegan 26°C (79°F) 17°C (63°F) 96 mm (3.8 in)

Illinois weather in August: frequently asked questions

What is the weather like in Illinois, the United States of America in August?

Expect pleasant weather across Illinois, the United States of America in August. The popular destination of Chicago averages 28°C (82°F) by day and 18°C (64°F) at night during this summer month.

What is the average temperature in Illinois, the United States of America in August?

Daytime temperatures in Chicago peak at roughly 28°C (82°F) in August, dropping to about 18°C (64°F) overnight.

Does Illinois, the United States of America get a lot of rain in August?

Yes, August tends to be a wetter month in Illinois, the United States of America. Average rainfall in Chicago sits around 115 mm (4.5 in).

Is August a Good Time to Visit Illinois, the United States of America?

In our opinion, August is a good time to visit Illinois, the United States of America with overall pleasant weather in Chicago.

Generally speaking, September provides perfect weather in Chicago. The weather in January, February, March, November and December, on the other hand, tends to be poor.

Interested in more climate information?

We have much more information about the climate in Illinois.

Weather and climate has detailed information for every country in the world. Are you going to the United States of America? Get detailed historical weather averages for many cities in the United States of America.

Not sure yet where to go? We now have a tool which recommends destinations that suit your ideal travel conditions. Find out where to go with our weather planner.

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