Jefferson County, IL: Current UV Index and Hourly Forecast

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As of 1:03 PM CST on January 20, 2026, all 10 cities in Jefferson County, IL in our database have a UV Index reading of Low. The city with the highest UV Index reading right now is Mount Vernon, IL with a reading of 1.7.

Over the next 24 hours, the highest UV Index reading in Jefferson County, IL is expected to be 1.7 in Mount Vernon between 1:00 PM - 2:00 PM CST today.

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Current UV Index in Cities in Jefferson County, IL

• Belle Rive - 1.7
• Bluford - 1.7
• Bonnie - 1.7
• Dix - 1.7
• Ina - 1.7
• Mount Vernon - 1.7
• Nason - 1.7
• Opdyke - 1.7
• Waltonville - 1.7
• Woodlawn - 1.7