Last updated: July 2, 2025
In Denver, United States, awareness of the UV Index is crucial for protecting your skin from the sun's harmful rays. Understanding UV levels not only helps in preventing painful sunburns but also plays a vital role in maintaining long-term skin health. With Denver's high-altitude climate and intense sun exposure—especially during the peak hours from 10 AM to 2 PM—it's essential to be proactive about sun safety. As the UV Index climbs to a maximum of 10 during summer afternoons, staying informed can make a significant difference in your outdoor activities and overall well-being.
The UV Index throughout the day paints a clear picture of sun intensity. Starting from a gentle 1 at 07:00, the UV levels gradually rise, peaking at an intense 10 by 13:00. This midday spike calls for caution as sun exposure increases significantly. As the afternoon progresses, from 14:00 to 15:00, the index slightly dips to 9 and 8, respectively, before gradually falling off to 6 at 16:00 and down to a mellow 1 by 19:00. For outdoor enthusiasts, the window between 11:00 and 13:00 is the time to enjoy the sun while remaining mindful of skin protection.
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 1 | low | 45 min |
| 08:00 | 2 | low | 45 min |
| 09:00 | 3 | moderate | 30 min |
| 10:00 | 5 | moderate | 30 min |
| 11:00 | 8 | very high | 15 min |
| 12:00 | 9 | very high | 15 min |
| 13:00 | 10 | very high | 15 min |
| 14:00 | 9 | very high | 15 min |
| 15:00 | 8 | very high | 15 min |
| 16:00 | 6 | high | 25 min |
| 17:00 | 4 | moderate | 30 min |
| 18:00 | 2 | low | 45 min |
| 19:00 | 1 | low | 45 min |
Throughout the year, the UV Index demonstrates significant seasonal fluctuations, with high-risk months typically occurring from April to September. In April, the UV Index escalates to 8, indicating very high exposure risks, and remains elevated through May (9) and June (11), where it reaches an extreme level. July (10) and August (9) continue to present very high risks, before tapering off in September (8). As a precaution, visitors and residents should take protective measures, especially during these peak months, by seeking shade, wearing protective clothing, and applying sunscreen frequently. In contrast, the UV Index drops to a moderate level (3-5) from October to March, allowing for safer outdoor activities during this period.
UV Risk Categories
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Denver | 3 | 5 | 5 | 8 | 9 | 11 | 10 | 9 | 8 | 5 | 3 | 3 |
| Chicago UVI | 3 | 4 | 6 | 8 | 9 | 10 | 10 | 9 | 8 | 6 | 4 | 2 |
| Brooklyn UVI | 3 | 5 | 6 | 8 | 10 | 10 | 9 | 9 | 8 | 6 | 4 | 2 |
| New York City UVI | 3 | 5 | 6 | 8 | 10 | 10 | 9 | 9 | 8 | 6 | 4 | 2 |
| Los Angeles UVI | 4 | 6 | 8 | 9 | 10 | 11 | 11 | 10 | 10 | 7 | 5 | 4 |
| Houston UVI | 5 | 8 | 9 | 11 | 11 | 12 | 12 | 11 | 10 | 9 | 7 | 5 |