Temperatures in August
It's warm in August in Illinois with an average temperature of 29°C. Temperatures this month range from a low of 27°C to a high of 31°C. At night, you can expect temperatures between 17°C and 20°C.
Max and Min Temperatures per Day
This chart shows the daily maximum and minimum temperatures in degrees Celsius for Illinois in August. The red line indicates the max temperatures, and the blue line shows the minimums.
Start of August
The month of August starts in Illinois with hot temperatures, averaging around 29°C during the day and nights close to 19°C. A few showers might pop up in the first days of the month, but the weather remains mostly sunny and dry.
Since temperatures can differ between day and night, it’s a good idea to dress in layers.
Mid-August
By mid-August, the average daytime temperature stays the same at 29°C, with nights close to 19°C. There might be a few showers during this period, but plenty of dry days with sunshine too.
Temperatures vary between day and night, so it’s smart to wear layers.
End of August
By the end of August, the average daytime temperature in Illinois will be around 29°C, with nights close to 19°C. There’s regular precipitation, but with a bit of luck, you’ll also get some dry and sunny days.
As it gets cooler in the evening, it’s best to wear layers.
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Precipitation in August
In August, there is an average of 92 mm of precipitation, spread over 9 days. The wind speed is around 3 Bft, mostly coming from the South.
The average precipitation chance is 29% per day this month. Though it seems pretty low, the weather’s variable. Some days have higher and others lower precipitation chances, which lowers the average.
Precipitation Chance
This chart shows the daily precipitation chance (in percentages) in August for Illinois. 0% means it never rained on that day in the past 10 years, and 100% means it rained every day. All values in between represent the average chance of precipitation on that day.
Illinois in August |
UK | ||
|---|---|---|---|
 Average Temperature |
29°C | 22°C | |
 High Temp |
31°C | 24°C | |
| Low Temp |
27°C | 19°C | |
 Total Precipitation |
92 mm | 60 mm | |
| Rainy Days |
9 days | 10 days | |
July
UV index
The UV index is a maximum of 2 this month. That's a low value on the intensity scale of 1 to 11. The risk of sunburn is minimal at this time.
Is August a good time to visit Illinois?
Want nice weather? Then August is a great time to be in Illinois. You’ll have pleasant temperatures and not too much rain this month.
Temperature records for Illinois in August
With 37°C, Illinois hit the highest temperature in the last 10 years in August 2023. The lowest daytime temperature in this month was 20°C in 2018. The extreme night temperatures ranged from a low of 10°C to a high of 26°C.
Check out the climate of Illinois for all months and discover the best travel time
The climate of Illinois is based on weather data from . Other spots, like New York City, Miami or Los Angeles, might have different weather. You can check out all destinations in Illinois for a full picture of the climate.
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Daily Temperature in August in Illinois
This chart shows the average daily temperatures, both day and night, for each day in August in Illinois, measured in degrees Celsius. The red line represents the maximum temperatures, while the blue line shows the minimums. The days of the month are displayed at the bottom of the chart. The data, based on historical observations, gives an overview of the average daily temperatures during this month.
Daily Precipitation in August in Illinois
The chart below shows the average daily precipitation in August for Illinois, measured in millimetres over the past years. Precipitation is always measured as water, even if it’s snow or hail. The days of the month are shown at the bottom of the chart.
A low average precipitation means that the chance of rain on that day is usually small, while a higher average suggests that rain is more likely. But it’s still an average, so each day can be different. Based on historical weather data for August, you can expect around 9 days of rain in Illinois.
Daily UV Index in August in Illinois
This chart shows the average daily UV index in August in Illinois, with the UV index ranging from 0 to a maximum of 11. The bottom of the chart shows the days of the month. Based on historical data, this chart provides an idea of the daily UV radiation levels you can expect.
Temperature in August in Illinois Over the Years
This chart shows the average temperature in August in Illinois, measured in degrees Celsius, over the past years.
Total Precipitation in August in Illinois Over the Years
This chart shows the average precipitation in August in Illinois, measured in millimetres over the past years. Precipitation is always measured as water, even if it’s snow or hail.
Daily climate in August for Illinois
Click on a specific day in August for detailed info on the typical weather on that day in Illinois. Check out the historical temperatures and precipitation over the past 10 years on this day.
Weather experiences in August in Illinois
Have you been to Illinois in August?
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Average Weather in Illinois by Month
Click on a month below to see detailed weather info for Illinois. Based on historical weather data, you can see the average temperature, precipitation, wind, and UV index for each day of the month.
