As of 3:57 PM CDT on October 7, 2025, out of 17 cities in St. Charles County, MO in our database, 16 cities (94%) have a UV Index reading of Moderate, while 1 city (6%) have a UV Index reading of Low. The city with the highest UV Index reading right now is West Alton, MO with a reading of 3.2.
Over the next 24 hours, the highest UV Index reading in St. Charles County, MO is expected to be 5.2 in Augusta between 1:00 PM - 2:00 PM CDT tomorrow.
| Range | 0 - 2 | 3 - 5 | 6 - 7 | 8 - 10 | 11+ |
|---|---|---|---|---|---|
| Color | |||||
| Risk | Low | Moderate | High | Very High | Extreme |