UV Index Today in McHenry County, Illinois (IL)

The average maximum UV Index today across 53 locations in McHenry County, Illinois (IL), is 8.4. The highest projected maximum is 8.5 in Algonquin at 1:00 PM CDT, while the lowest projected maximum is 8.4 in Grafton at 1:00 PM CDT.

Tomorrow, the average maximum UV Index across those same locations is expected to be 5.1. The highest projected maximum is 5.8 in Marengo at 1:00 PM CDT, and the lowest projected maximum is 3.7 in Fox Lake at 12:00 PM CDT.