McHenry County, IL: Current UV Index and Hourly Forecast

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As of 6:58 PM CDT on April 29, 2026, all 40 cities in McHenry County, IL in our database have a UV Index reading of Low. The city with the highest UV Index reading right now is Harvard, IL with a reading of 0.7.

Over the next 24 hours, the highest UV Index reading in McHenry County, IL is expected to be 6.1 in Crystal Lake between 12:00 PM - 1:00 PM CDT tomorrow.

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Current UV Index in Cities in McHenry County, IL

• Alden - 0.7
• Algonquin - 0.6
• Big Foot Prairie - 0.7
• Bull Valley - 0.6
• Burtons Bridge - 0.6
• Cary - 0.6
• Chemung - 0.7
• Coral - 0.6
• Crystal Lake - 0.6
• Fox River Grove - 0.6
• Franklinville - 0.6
• Greenwood - 0.7
• Harmony - 0.6
• Hartland - 0.6
• Harvard - 0.7
• Hebron - 0.7
• Holiday Hills - 0.6
• Huntley - 0.6
• Island Lake - 0.6
• Johnsburg - 0.4
• Lake in the Hills - 0.6
• Lakemoor - 0.6
• Lakewood - 0.6
• Lawrence - 0.7
• Marengo - 0.6
• McCullom Lake - 0.6
• McHenry - 0.6
• Oakwood Hills - 0.6
• Pistakee Highlands - 0.4
• Prairie Grove - 0.6
• Richmond - 0.4
• Ridgefield - 0.6
• Riley - 0.7
• Ringwood - 0.4
• Solon Mills - 0.4
• Spring Grove - 0.4
• Trout Valley - 0.6
• Union - 0.6
• Wonder Lake - 0.4
• Woodstock - 0.6