As of 12:56 PM CDT on August 29, 2025, all 18 cities in Williamson County, TX in our database have a UV Index reading of Very High. The city with the highest UV Index reading right now is Round Rock, TX with a reading of 9.
Over the next 24 hours, the highest UV Index reading in Williamson County, TX is expected to be 10.8 in Liberty Hill between 2:00 PM - 3:00 PM CDT today.
| Range | 0 - 2 | 3 - 5 | 6 - 7 | 8 - 10 | 11+ |
|---|---|---|---|---|---|
| Color | |||||
| Risk | Low | Moderate | High | Very High | Extreme |