As of 11:10 AM MST on January 13, 2026, all 4 cities in Costilla County, CO in our database have a UV Index reading of Low. The city with the highest UV Index reading right now is San Luis, CO with a reading of 2.2.
Over the next 24 hours, the highest UV Index reading in Costilla County, CO is expected to be 2.7 in San Luis between 12:00 PM - 1:00 PM MST today.
| Range | 0 - 2 | 3 - 5 | 6 - 7 | 8 - 10 | 11+ |
|---|---|---|---|---|---|
| Color | |||||
| Risk | Low | Moderate | High | Very High | Extreme |