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United StatesThe weather in August in Illinois
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.
Looking for great weather? August is a good time to be in Illinois. The temperatures are nice, and there’s not too much rain.
Average temperatures and precipitation
This chart shows the average daily maximum and minimum temperatures (in degrees Celsius) and precipitation (in millimeters) in August for Illinois, United States. A low precipitation value usually indicates little to no rainfall on that day in recent years, while a higher value suggests more frequent rainfall.
Temperature records
With 37°C in 2023, Illinois reached the highest temperature in August over the past 10 years. The lowest daytime temperature in this month was 20°C in 2018. The extreme nighttime temperatures ranged from a lowest recorded value of 10°C to a highest value of 26°C.
Rainfall amount
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.
Daily weather in August for Illinois
Click on any day in August to get detailed info about the usual weather on that day in Illinois. Check out the historical temperatures and precipitation over the past 10 years on this day.
August weather comparison
| Illinois | New York | |
|---|---|---|
| Average temperature | 29°C | 30°C |
| Max. temperature | 31°C | 31°C |
| Min. temperature | 17°C | -5°C |
| Total precipitation | 92 mm | 79 mm |
| Rainy days | 12 days | 13 days |
Start of August
The month of August starts in Illinois with hot temps, averaging around 29°C during the day and nights around 19°C.
Mid August
By mid-August, daytime temps stay steady at around 29°C, with nights around 19°C. There’s a chance of some showers during this time, but plenty of dry and sunny days too.
End of August
By the end of August, the average daytime temperature in Illinois is around 29°C, while nighttime temps are about 19°C. Expect regular precipitation, but if you’re lucky, you’ll also get some dry and sunny days.
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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.
Check out the climate of Illinois for all months and discover the best travel time
The climate in Illinois is based on weather data from . Other places, like New York City, Miami or Los Angeles, might have different weather. You can check out all destinations in Illinois to get the full picture of the climate.
Temperature charts
These charts show the average temperatures in August in Illinois, United States. The temperatures are shown in degrees Celsius and are calculated based on data from the past 10 years.
Daily Temperature in August in Illinois
Temperature in August in Illinois over the years
Precipitation charts
These charts show the average amount of precipitation in August in Illinois, United States. Precipitation is always measured as water, even when it falls as snow or hail The amount of precipitation is displayed in millimeters, while snowfall is shown in centimeters.
Daily Precipitation in August in Illinois
Total precipitation in August in Illinois over the years
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.
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.