Illinois (Chicago)
May
Weather in Illinois for May 2025
Your guide to Illinois weather in May - trends and predictions
In general, the average temperature in Illinois at the beginning of May is 15.7 °F. As the month progressed, temperatures tended to significantly warm up, reaching an average of 18.9 °F by the end of May.
Illinois sees moderate rainfall in May, averaging 6 rainy days.
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25
Dry days
6
Rainy days
0
Snow days
20°/9°
Temperatures
19 km/h
Avg max wind
71 %
Avg humidity
Illinois in May average weather
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| Mon. | Tue. | Wed. | Thu. | Fri. | Sat. | Sun. |
|---|---|---|---|---|---|---|
| 1  13° | 2  13° | 3  14° | 4 17° | |||
| 5 16° | 6 16° | 7 21° | 8 17° | 9  12° | 10  15° | 11 18° |
| 12 20° | 13 18° | 14 12° | 15 14° | 16 20° | 17 17° | 18 20° |
| 19 19° | 20 21° | 21 23° | 22 21° | 23  22° | 24 20° | 25 16° |
| 26 19° | 27 18° | 28 19° | 29 17° | 30 20° | 31  23° |
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Temperatures trend during May in Illinois
See the weather trend as well as the moving average line
May weather day by day
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| Date | Weather | Temperatures | Rain | UV | More |
|---|---|---|---|---|---|
| May 1 | Moderate rain at times | 13° /7° | 4.3 mm | 3 | |
| May 2 | Patchy rain possible | 13° /6° | 6 mm | 3 | |
| May 3 | Partly cloudy | 14° /5° | 3.6 mm | 4 | |
| May 4 | Partly cloudy | 17° /7° | 2.4 mm | 5 | |
| May 5 | Partly cloudy | 16° /9° | 0.1 mm | 4 | |
| May 6 | Moderate or heavy rain shower | 16° /9° | 5 mm | 5 | |
| May 7 | Moderate or heavy rain shower | 21° /11° | 23.2 mm | 5 | |
| May 8 | Moderate or heavy rain shower | 17° /12° | 23.9 mm | 4 | |
| May 9 | Overcast | 12° /8° | 4.6 mm | 3 | |
| May 10 | Cloudy | 15° /8° | 0.5 mm | 4 | |
| May 11 | Partly cloudy | 18° /11° | 1.2 mm | 5 | |
| May 12 | Moderate or heavy rain shower | 20° /12° | 7.4 mm | 5 | |
| May 13 | Overcast | 18° /12° | 12.5 mm | 5 | |
| May 14 | Patchy rain possible | 12° /8° | 8.2 mm | 3 | |
| May 15 | Overcast | 14° /9° | 0.9 mm | 3 | |
| May 16 | Overcast | 20° /10° | 0.4 mm | 5 | |
| May 17 | Partly cloudy | 17° /11° | 3.9 mm | 4 | |
| May 18 | Overcast | 20° /11° | 0.1 mm | 5 | |
| May 19 | Moderate or heavy rain shower | 19° /12° | 9.9 mm | 5 | |
| May 20 | Partly cloudy | 21° /10° | 0.8 mm | 6 | |
| May 21 | Partly cloudy | 23° /14° | 4 mm | 6 | |
| May 22 | Partly cloudy | 21° /13° | 0.5 mm | 6 | |
| May 23 | Sunny | 22° /14° | 0 mm | 6 | |
| May 24 | Cloudy | 20° /12° | 8 mm | 5 | |
| May 25 | Sunny | 16° /10° | 0 mm | 5 | |
| May 26 | Partly cloudy | 19° /12° | 6.9 mm | 5 | |
| May 27 | Partly cloudy | 18° /12° | 2.4 mm | 5 | |
| May 28 | Partly cloudy | 19° /12° | 1.7 mm | 5 | |
| May 29 | Sunny | 17° /11° | 0 mm | 5 | |
| May 30 | Overcast | 20° /12° | 0 mm | 5 | |
| May 31 | Heavy rain at times | 23° /14° | 1.5 mm | 6 | |
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Important Notice
Our weather forecast for Illinois in May 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 May - FAQ
What are the expected maximum and minimum temperatures in Illinois during May?
Enjoy moderate daytime temperatures of up to 20° and cooler nights around 9°. Ideal for a range of outdoor activities, from hiking to city tours.
How much rainfall should be expected in Illinois during May?
Significant rainfall exceeding 265.8 mm is expected in Illinois during May, occurring over more than 6 days. Preparing for wet conditions is recommended in your planning.
What are the typical wind conditions in Illinois during May?
The average wind speed in Illinois during May is 19 km/h, suggesting breezy to windy conditions, depending on your activities.
May rainfall patterns in Illinois
Explore the daily rainfall trends and prepare for Illinoiss May weather 💧
UV exposure in Illinois during May
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