McHenry County, IL: Current UV Index and Hourly Forecast

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As of 3:40 PM CDT on April 9, 2026, all 40 cities in McHenry County, IL in our database have a UV Index reading of Moderate. The city with the highest UV Index reading right now is Chemung, IL with a reading of 4.

Over the next 24 hours, the highest UV Index reading in McHenry County, IL is expected to be 5 in Chemung between 2:00 PM - 3:00 PM CDT tomorrow.

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Current UV Index in Cities in McHenry County, IL

• Alden - 3.8
• Algonquin - 3.5
• Big Foot Prairie - 3.8
• Bull Valley - 3.5
• Burtons Bridge - 3.5
• Cary - 3.5
• Chemung - 4
• Coral - 3.8
• Crystal Lake - 3.5
• Fox River Grove - 3.5
• Franklinville - 3.8
• Greenwood - 3.8
• Harmony - 3.8
• Hartland - 3.8
• Harvard - 3.8
• Hebron - 3.8
• Holiday Hills - 3.5
• Huntley - 3.8
• Island Lake - 3.5
• Johnsburg - 3.6
• Lake in the Hills - 3.5
• Lakemoor - 3.5
• Lakewood - 3.8
• Lawrence - 4
• Marengo - 3.8
• McCullom Lake - 3.5
• McHenry - 3.5
• Oakwood Hills - 3.5
• Pistakee Highlands - 3.6
• Prairie Grove - 3.5
• Richmond - 3.6
• Ridgefield - 3.5
• Riley - 3.9
• Ringwood - 3.6
• Solon Mills - 3.6
• Spring Grove - 3.6
• Trout Valley - 3.5
• Union - 3.8
• Wonder Lake - 3.6
• Woodstock - 3.8