UV Index Today in St. Clair County, Illinois (IL)

The average maximum UV Index today across 50 locations in St. Clair County, Illinois (IL), is 2. The highest projected maximum is 2.4 in St. Louis at 12:00 PM CST, while the lowest projected maximum is 1.6 in O'Fallon at 10:00 AM CST.

Tomorrow, the average maximum UV Index across those same locations is expected to be 3.2. The highest projected maximum is 3.3 in New Athens at 12:00 PM CST, and the lowest projected maximum is 3.1 in St. Louis at 12:00 PM CST.