Peak UV index by city
| City | Population | Peak UV | Exposure | UV 3+ hours |
|---|---|---|---|---|
| Denver | 740,613 | 3 | Moderate | 11 AM–2 PM |
| Colorado Springs | 494,743 | 4 | Moderate | 11 AM–2 PM |
| Aurora | 410,053 | 3 | Moderate | 11 AM–2 PM |
| Fort Collins | 171,500 | 3 | Moderate | 11 AM–2 PM |
| Lakewood | 156,927 | 3 | Moderate | 11 AM–2 PM |
| Thornton | 147,766 | 3 | Moderate | 11 AM–2 PM |
| Arvada | 122,901 | 3 | Moderate | 11 AM–2 PM |
| Westminster | 116,182 | 3 | Moderate | 11 AM–2 PM |
| Greeley | 115,073 | 3 | Moderate | 11 AM–2 PM |
| Pueblo | 110,404 | 4 | Moderate | 11 AM–2 PM |
| Centennial | 108,658 | 3 | Moderate | 11 AM–2 PM |
| Boulder | 105,689 | 3 | Moderate | 11 AM–2 PM |
| Longmont | 100,109 | 3 | Moderate | 11 AM–2 PM |
| Castle Rock | 83,815 | 4 | Moderate | 11 AM–2 PM |
| Loveland | 81,387 | 3 | Moderate | 11 AM–2 PM |
| Broomfield | 79,174 | 3 | Moderate | 11 AM–2 PM |
| Commerce City | 72,345 | 3 | Moderate | 11 AM–2 PM |
| Grand Junction | 71,827 | 3 | Moderate | 12 PM–1 PM |
| Parker | 65,985 | 3 | Moderate | 11 AM–2 PM |
| Littleton | 46,246 | 3 | Moderate | 11 AM–2 PM |
| Brighton | 45,395 | 3 | Moderate | 11 AM–2 PM |
| Windsor | 43,840 | 3 | Moderate | 11 AM–2 PM |
| Erie | 40,904 | 3 | Moderate | 11 AM–2 PM |
| Northglenn | 38,893 | 3 | Moderate | 11 AM–2 PM |
| Englewood | 35,305 | 3 | Moderate | 11 AM–2 PM |
| Wheat Ridge | 32,081 | 3 | Moderate | 11 AM–2 PM |
| Lafayette | 30,116 | 3 | Moderate | 11 AM–2 PM |
| Fountain | 29,450 | 4 | Moderate | 11 AM–2 PM |
UV 3+ hours show the window from the first forecast hour at 3 or above to the end of the last. The EPA recommends sun protection at UV 3 and above. Open a city for its current-hour forecast and hourly chart. Forecast sources and limitations.