As of 2:22 AM MDT on July 23, 2026, all 23 cities in Jefferson County, CO in our database have a UV Index reading of 0, indicating no radiation from the sun.
Over the next 24 hours, the highest UV Index reading in Jefferson County, CO is expected to be 11.3 in Ken Caryl between 1:00 PM - 2:00 PM MDT today.
| Range | 0 - 2 | 3 - 5 | 6 - 7 | 8 - 10 | 11+ |
|---|---|---|---|---|---|
| Color | |||||
| Risk | Low | Moderate | High | Very High | Extreme |