As of 1:28 PM MDT on August 17, 2026, all 18 cities in Lewis and Clark County, MT in our database have a UV Index reading of High. The city with the highest UV Index reading right now is Augusta, MT with a reading of 6.2.
Over the next 24 hours, the highest UV Index reading in Lewis and Clark County, MT is expected to be 6.7 in Rimini between 2:00 PM - 3:00 PM MDT today.
| Range | 0 - 2 | 3 - 5 | 6 - 7 | 8 - 10 | 11+ |
|---|---|---|---|---|---|
| Color | |||||
| Risk | Low | Moderate | High | Very High | Extreme |