Illinois
August
Weather in Illinois for August 2025
Your guide to Illinois weather in August - trends and predictions
In general, the average temperature in Illinois at the beginning of August is 26.1 °F. As the month progressed, temperatures tended to slightly increase, reaching an average of 26.6 °F by the end of August.
The climate of Illinois in August is notably wet, with an average of 14 rainy days.
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17
Dry days
14
Rainy days
0
Snow days
26°/19°
Temperatures
20 km/h
Avg max wind
70 %
Avg humidity
Illinois in August average weather
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| Mon. | Tue. | Wed. | Thu. | Fri. | Sat. | Sun. |
|---|---|---|---|---|---|---|
| 1  29° | 2  27° | 3 28° | ||||
| 4 27° | 5  26° | 6 22° | 7  24° | 8 26° | 9 25° | 10 25° |
| 11 26° | 12 23° | 13 25° | 14 24° | 15 23° | 16 28° | 17 24° |
| 18  24° | 19 25° | 20 26° | 21 23° | 22 26° | 23 31° | 24  33° |
| 25 28° | 26 28° | 27 28° | 28 26° | 29 27° | 30 25° | 31 24° |
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Temperatures trend during August in Illinois
See the weather trend as well as the moving average line
August weather day by day
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| Date | Weather | Temperatures | Rain | UV | More |
|---|---|---|---|---|---|
| Aug. 1 | Patchy rain possible | 29° /21° | 3.8 mm | 6 | |
| Aug. 2 | Overcast | 27° /21° | 1.6 mm | 6 | |
| Aug. 3 | Overcast | 28° /21° | 0.1 mm | 6 | |
| Aug. 4 | Patchy rain possible | 27° /20° | 0.3 mm | 7 | |
| Aug. 5 | Heavy rain at times | 26° /21° | 3.8 mm | 6 | |
| Aug. 6 | Patchy rain possible | 22° /19° | 10.2 mm | 5 | |
| Aug. 7 | Moderate or heavy rain shower | 24° /18° | 3.5 mm | 6 | |
| Aug. 8 | Patchy rain possible | 26° /18° | 0.6 mm | 6 | |
| Aug. 9 | Overcast | 25° /17° | 0 mm | 6 | |
| Aug. 10 | Patchy rain possible | 25° /15° | 0.2 mm | 6 | |
| Aug. 11 | Patchy rain possible | 26° /17° | 0.5 mm | 6 | |
| Aug. 12 | Moderate or heavy rain shower | 23° /18° | 4.5 mm | 6 | |
| Aug. 13 | Patchy rain possible | 25° /18° | 0.7 mm | 7 | |
| Aug. 14 | Moderate or heavy rain shower | 24° /19° | 12.7 mm | 6 | |
| Aug. 15 | Patchy rain possible | 23° /17° | 6.7 mm | 5 | |
| Aug. 16 | Overcast | 28° /18° | 8 mm | 6 | |
| Aug. 17 | Moderate or heavy rain shower | 24° /18° | 10.9 mm | 6 | |
| Aug. 18 | Sunny | 24° /18° | 0.7 mm | 6 | |
| Aug. 19 | Sunny | 25° /18° | 0 mm | 6 | |
| Aug. 20 | Sunny | 26° /19° | 0 mm | 7 | |
| Aug. 21 | Overcast | 23° /18° | 0 mm | 6 | |
| Aug. 22 | Overcast | 26° /18° | 0 mm | 6 | |
| Aug. 23 | Overcast | 31° /20° | 0 mm | 8 | |
| Aug. 24 | Cloudy | 33° /20° | 0.1 mm | 8 | |
| Aug. 25 | Cloudy | 28° /20° | 2.6 mm | 6 | |
| Aug. 26 | Overcast | 28° /20° | 1 mm | 6 | |
| Aug. 27 | Cloudy | 28° /21° | 0 mm | 6 | |
| Aug. 28 | Sunny | 26° /19° | 2.3 mm | 7 | |
| Aug. 29 | Light rain shower | 27° /19° | 2.3 mm | 6 | |
| Aug. 30 | Overcast | 25° /19° | 8.4 mm | 6 | |
| Aug. 31 | Sunny | 24° /18° | 0.4 mm | 7 | |
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Important Notice
Our weather forecast for Illinois in August is based on the analysis of historical data rather than real-time forecast models. While this provides a general overview, weather conditions can change. We recommend that you check the Illinois forecast closer to your planned date for the most up-to-date weather information.
Illinois in August - FAQ
What are the expected maximum and minimum temperatures in Illinois during August?
During August, expect a variety of temperatures with highs around 26° and lows near 19°, suitable for diverse activities and preferences.
How much rainfall should be expected in Illinois during August?
Moderate rainfall is anticipated in Illinois during August, with a total of 75.8 mm spread over approximately 14 days. Considering plans for rainy days is advisable.
What are the typical wind conditions in Illinois during August?
The average wind speed in Illinois during August is 20 km/h, suggesting breezy to windy conditions, depending on your activities.
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