As of 9:51 AM CDT on September 21, 2026, all 8 cities in Grant County, SD in our database have a UV Index reading of Low. The city with the highest UV Index reading right now is Milbank, SD with a reading of 0.1.
Over the next 24 hours, the highest UV Index reading in Grant County, SD is expected to be 2.5 in Marvin between 1:00 PM - 2:00 PM CDT today.
| Range | 0 - 2 | 3 - 5 | 6 - 7 | 8 - 10 | 11+ |
|---|---|---|---|---|---|
| Color | |||||
| Risk | Low | Moderate | High | Very High | Extreme |