McHenry County, IL: Current UV Index and Hourly Forecast

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As of 7:34 AM CDT on May 17, 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 0.4.

Over the next 24 hours, the highest UV Index reading in McHenry County, IL is expected to be 6 in Harvard between 2:00 PM - 3:00 PM CDT today.

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Current UV Index in Cities in McHenry County, IL

• Alden - 0.4
• Algonquin - 0.3
• Big Foot Prairie - 0.4
• Bull Valley - 0.3
• Burtons Bridge - 0.3
• Cary - 0.3
• Chemung - 0.4
• Coral - 0.3
• Crystal Lake - 0.3
• Fox River Grove - 0.3
• Franklinville - 0.3
• Greenwood - 0.4
• Harmony - 0.3
• Hartland - 0.3
• Harvard - 0.4
• Hebron - 0.4
• Holiday Hills - 0.3
• Huntley - 0.3
• Island Lake - 0.3
• Johnsburg - 0.3
• Lake in the Hills - 0.3
• Lakemoor - 0.3
• Lakewood - 0.3
• Lawrence - 0.4
• Marengo - 0.3
• McCullom Lake - 0.3
• McHenry - 0.3
• Oakwood Hills - 0.3
• Pistakee Highlands - 0.3
• Prairie Grove - 0.3
• Richmond - 0.3
• Ridgefield - 0.3
• Riley - 0.4
• Ringwood - 0.3
• Solon Mills - 0.3
• Spring Grove - 0.3
• Trout Valley - 0.3
• Union - 0.3
• Wonder Lake - 0.3
• Woodstock - 0.3