As of 3:41 PM CDT on September 16, 2025, out of 8 cities in Union County, IA in our database, 7 cities (88%) have a UV Index reading of Moderate, while 1 city (13%) have a UV Index reading of Low. The city with the highest UV Index reading right now is Cromwell, IA with a reading of 4.6.
Over the next 24 hours, the highest UV Index reading in Union County, IA is expected to be 6.2 in Thayer 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 |