Illinois weather in April
April is one of the least pleasant months in Illinois: highs of 10°C (50°F) and about 95 mm (3.7 in) of rain on average. Nights average 4°C (39°F) and cloud cover 63% (NASA POWER, 2001–2025 averages). It is the 5th wettest month of the year and the 6th coolest. Compared with March, it is warmer and wetter; May brings highs of 15°C (59°F) and 117 mm (4.6 in) of rain.
Figures are long-term averages for Chicago, the largest city in Illinois. See below for other places.
Is April a good time to visit Illinois?
least pleasant month Weather score 42/100.
April is one of the least pleasant months for weather in Illinois. For better conditions, consider Jun–Sep.
Does it rain a lot in Illinois in April?
Some rain is normal: about 95 mm (3.7 in) falls in an average April. It is the 5th wettest month of the year.
How warm is Illinois in April?
Days average 10°C (50°F) and nights 4°C (39°F).
Illinois weather by month
| Month | High | Low | Rain | Cloud | Weather |
|---|---|---|---|---|---|
| January | 0°C (32°F) | -5°C (23°F) | 48 mm | 71% | least pleasant |
| February | 0°C (33°F) | -5°C (23°F) | 54 mm | 70% | least pleasant |
| March | 5°C (41°F) | -1°C (31°F) | 62 mm | 66% | least pleasant |
| April | 10°C (50°F) | 4°C (39°F) | 95 mm | 63% | least pleasant |
| May | 15°C (59°F) | 9°C (47°F) | 117 mm | 64% | fair |
| June | 21°C (70°F) | 15°C (59°F) | 102 mm | 56% | best |
| July | 25°C (77°F) | 20°C (68°F) | 95 mm | 48% | best |
| August | 25°C (77°F) | 20°C (68°F) | 105 mm | 48% | best |
| September | 22°C (71°F) | 16°C (62°F) | 86 mm | 46% | best |
| October | 15°C (59°F) | 10°C (49°F) | 99 mm | 58% | fair |
| November | 9°C (47°F) | 4°C (38°F) | 61 mm | 63% | least pleasant |
| December | 3°C (37°F) | -2°C (29°F) | 58 mm | 73% | least pleasant |
Sources: 2001–2025 monthly averages from NASA POWER (MERRA-2 reanalysis). Page updated . How we rate months
Weather across Illinois in April
Weather can differ a lot within Illinois: coasts, hills and mountains each have their own climate.
| Place | High | Low | Rain | Weather |
|---|---|---|---|---|
| Chicago | 10°C (50°F) | 4°C (39°F) | 95 mm | least pleasant |
| Aurora | 15°C (58°F) | 3°C (37°F) | 95 mm | fair |
| Rockford | 14°C (58°F) | 2°C (36°F) | 93 mm | fair |
| Joliet | 16°C (61°F) | 3°C (38°F) | 95 mm | fair |
| Naperville | 15°C (58°F) | 3°C (37°F) | 95 mm | fair |
| Peoria | 18°C (64°F) | 5°C (41°F) | 98 mm | fair |
| Springfield | 18°C (65°F) | 6°C (42°F) | 103 mm | best |
| North Peoria | 18°C (64°F) | 5°C (41°F) | 98 mm | fair |
| Elgin | 15°C (58°F) | 3°C (37°F) | 95 mm | fair |
| Waukegan | 13°C (56°F) | 2°C (36°F) | 92 mm | fair |
| West Town | 10°C (50°F) | 4°C (39°F) | 95 mm | least pleasant |
| Champaign | 18°C (64°F) | 5°C (42°F) | 103 mm | best |