McHenry County, IL: Current UV Index and Hourly Forecast

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As of 1:39 PM CDT on April 21, 2025, 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 Riley, IL with a reading of 3.3.

Over the next 24 hours, the highest UV Index reading in McHenry County, IL is expected to be 6.6 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 - 2.7
• Algonquin - 2.7
• Big Foot Prairie - 2.7
• Bull Valley - 2.7
• Burtons Bridge - 2.7
• Cary - 2.7
• Chemung - 2.8
• Coral - 3
• Crystal Lake - 2.7
• Fox River Grove - 2.7
• Franklinville - 3
• Greenwood - 2.7
• Harmony - 3
• Hartland - 3
• Harvard - 2.7
• Hebron - 2.7
• Holiday Hills - 2.7
• Huntley - 3
• Island Lake - 2.7
• Johnsburg - 2.7
• Lake in the Hills - 2.7
• Lakemoor - 2.7
• Lakewood - 3
• Lawrence - 2.8
• Marengo - 3
• McCullom Lake - 2.7
• McHenry - 2.7
• Oakwood Hills - 2.7
• Pistakee Highlands - 2.7
• Prairie Grove - 2.7
• Richmond - 2.7
• Ridgefield - 2.7
• Riley - 3.3
• Ringwood - 2.7
• Solon Mills - 2.7
• Spring Grove - 2.7
• Trout Valley - 2.7
• Union - 3
• Wonder Lake - 2.7
• Woodstock - 3