Normal weather for Illinois 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.
In August, there is an average of 92 mm of precipitation, spread over 12 days. The wind speed is around 3 Bft, mostly coming from the South.
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.
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 |
12 days | 10 days | |
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.
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.
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.
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.
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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.
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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 12 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
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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.
