As of 10:00 AM MDT on May 4, 2026, all 4 cities in Costilla County, CO in our database have a UV Index reading of Moderate. The city with the highest UV Index reading right now is Fort Garland, CO with a reading of 3.6.
Over the next 24 hours, the highest UV Index reading in Costilla County, CO is expected to be 6.3 in San Luis 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 |