As of 1:57 PM CDT on August 31, 2026, out of 119 cities in Cook County, IL in our database, 70 cities (59%) have a UV Index reading of High, while 49 cities (41%) have a UV Index reading of Moderate. The city with the highest UV Index reading right now is Calumet City, IL with a reading of 6.5.
Over the next 24 hours, the highest UV Index reading in Cook County, IL is expected to be 7.2 in Calumet City between 12:00 PM - 1:00 PM CDT tomorrow.
| Range | 0 - 2 | 3 - 5 | 6 - 7 | 8 - 10 | 11+ |
|---|---|---|---|---|---|
| Color | |||||
| Risk | Low | Moderate | High | Very High | Extreme |