St. Clair County, IL: Current UV Index and Hourly Forecast

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As of 4:00 PM CDT on August 6, 2026, out of 32 cities in St. Clair County, IL in our database, 27 cities (84%) have a UV Index reading of Moderate, while 5 cities (16%) have a UV Index reading of Low. The city with the highest UV Index reading right now is Belleville, IL with a reading of 4.2.

Over the next 24 hours, the highest UV Index reading in St. Clair County, IL is expected to be 8.5 in Belleville between 1:00 PM - 2:00 PM CDT tomorrow.

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Current UV Index in Cities in St. Clair County, IL

• Alorton - 4.2
• Belleville - 4.2
• Brooklyn - 3.8
• Cahokia - 4.1
• Caseyville - 4.1
• Centreville - 4.2
• Darmstadt - 2.1
• Dupo - 4.1
• East Carondelet - 4.1
• East St. Louis - 4.1
• Fairmont City - 4.1
• Fairview Heights - 4.2
• Fayetteville - 3.8
• Floraville - 4.2
• Freeburg - 4.2
• Lebanon - 3.8
• Lenzburg - 2.1
• Marissa - 2.1
• Mascoutah - 3.8
• Millstadt - 4.2
• New Athens - 2.1
• O'Fallon - 4.2
• Paderborn - 3.9
• Rentchler - 3.8
• Sauget - 4.1
• Scott AFB - 3.8
• Shiloh - 4.2
• Smithton - 4.2
• St. Libory - 2.1
• Summerfield - 3.8
• Swansea - 4.2
• Washington Park - 4.1