Grayson County, TX: Current UV Index and Hourly Forecast

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As of 3:44 PM CDT on July 17, 2025, all 18 cities in Grayson County, TX in our database have a UV Index reading of Very High. The city with the highest UV Index reading right now is Collinsville, TX with a reading of 9.7.

Over the next 24 hours, the highest UV Index reading in Grayson County, TX is expected to be 11.3 in Pottsboro between 1:00 PM - 2:00 PM CDT tomorrow.

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Current UV Index in Cities in Grayson County, TX

• Bells - 9.6
• Collinsville - 9.7
• Denison - 9.5
• Dorchester - 9.6
• Gunter - 9.6
• Howe - 9.6
• Knollwood - 9.5
• Pottsboro - 9.5
• Preston - 9.5
• Sadler - 9.5
• Sherman - 9.5
• Sherwood Shores - 9.5
• Southmayd - 9.6
• Tioga - 9.7
• Tom Bean - 9.6
• Van Alstyne - 9.6
• Whitesboro - 9.6
• Whitewright - 9.6