As of 2:56 PM PDT on May 1, 2026, all 50 cities in Contra Costa County, CA in our database have a UV Index reading of High. The city with the highest UV Index reading right now is San Ramon, CA with a reading of 7.3.
Over the next 24 hours, the highest UV Index reading in Contra Costa County, CA is expected to be 7.3 in San Ramon between 2:00 PM - 3:00 PM PDT today.
| Range | 0 - 2 | 3 - 5 | 6 - 7 | 8 - 10 | 11+ |
|---|---|---|---|---|---|
| Color | |||||
| Risk | Low | Moderate | High | Very High | Extreme |