Last updated: June 24, 2025
In September, the average temperature in Chicago Heights, United States is a pleasant 20°C (68°F). However, be prepared for temperature variations, as it can dip to a cool 4°C (39°F) or soar to a warm 34°C (94°F). Expect around 80 mm (3.1 in) of precipitation spread over 9 days, and a relatively high average humidity of 80%.
In September in Chicago Heights, the average temperature is 20°C (68°F). Maximum temperatures can reach 34°C (94°F), while minimums can dip as low as 4°C (39°F). It's a great time to visit for a mix of warm days and cooler evenings, perfect for outdoor adventures and exploration.
In Chicago Heights in September, the precipitation amount is 80 mm (3.1 in) spread over 9 days.
In Chicago Heights in September, humidity is 80%. With an average temperature of 20°C (68°F), this humidity feels like traveling through a warm, dense blanket that clings to your skin, making you feel both sticky and lethargic as you explore the sights.
In Chicago Heights in September, the maximum UV index is 8, which corresponds to a very high Exposure Category. This means that the time to burn is only 15 minutes. For more detailed information, you can refer to the Hourly UV Index in Chicago Heights.
UV Risk Categories
Weather in Chicago Heights varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in Chicago Heights, focusing on differences in temperature, rainfall, humidity, and UV levels.
| Temperature | Precipitation | Humidity | UV | |
|---|---|---|---|---|
| January Weather | -3°C (27°F) | 66 mm (2.6 inches) | 82% | moderate |
| February Weather | -2°C (29°F) | 69 mm (2.7 inches) | 83% | moderate |
| March Weather | 4°C (40°F) | 96 mm (3.8 inches) | 84% | high |
| April Weather | 9°C (49°F) | 122 mm (4.8 inches) | 85% | very high |
| May Weather | 16°C (61°F) | 163 mm (6.4 inches) | 79% | very high |
| June Weather | 22°C (72°F) | 143 mm (5.6 inches) | 82% | very high |
| July Weather | 24°C (76°F) | 114 mm (4.5 inches) | 80% | very high |
| August Weather | 23°C (73°F) | 92 mm (3.6 inches) | 81% | very high |
| September Weather | 20°C (68°F) | 80 mm (3.1 inches) | 80% | very high |
| October Weather | 13°C (55°F) | 139 mm (5.5 inches) | 82% | high |
| November Weather | 4°C (40°F) | 63 mm (2.5 inches) | 88% | moderate |
| December Weather | 1°C (34°F) | 57 mm (2.2 inches) | 84% | low |