As of 6:12 AM MST on March 5, 2026, all 13 cities in Yellowstone County, MT 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 Yellowstone County, MT is expected to be 2.4 in Custer between 12:00 PM - 1:00 PM MST today.
| Range | 0 - 2 | 3 - 5 | 6 - 7 | 8 - 10 | 11+ |
|---|---|---|---|---|---|
| Color | |||||
| Risk | Low | Moderate | High | Very High | Extreme |