Last updated: May 3, 2025
Understanding the UV Index is crucial for residents and visitors in Boulder City, United States, a region known for its sunny climate and outdoor activities. With UV levels peaking at a significant 11 during midday hours, awareness of these levels is essential for preventing sunburn and protecting skin health. By recognizing the daily fluctuations in UV intensity, you can make informed decisions about sun safety—whether you're hiking, lounging by the pool, or exploring the beautiful landscapes that Boulder City has to offer. Stay sun smart and enjoy the great outdoors safely!
At 07:00, the UV Index starts at a gentle 1, perfect for a leisurely morning stroll. As the sun climbs, it reaches 3 by 08:00, signaling a slight increase in UV intensity. By 09:00, the index escalates to 5, becoming more noticeable. The real peak occurs between 12:00 and 13:00, where it spikes to a striking 11, indicating a high level of UV exposure—time to lather on that sunscreen! As the afternoon progresses, the UV Index gradually declines, dipping to 9 at 14:00, followed by 7 at 15:00. By 16:00, it settles at 4, and as the day winds down, it drops to 2 by 17:00 before returning to a low 1 at 18:00 and 19:00. Be sure to stay protected during the peak hours to enjoy the beautiful day safely!
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 1 | low | 45 min |
| 08:00 | 3 | moderate | 30 min |
| 09:00 | 5 | moderate | 30 min |
| 10:00 | 7 | high | 25 min |
| 11:00 | 9 | very high | 15 min |
| 12:00 | 11 | extreme | 10 min |
| 13:00 | 11 | extreme | 10 min |
| 14:00 | 9 | very high | 15 min |
| 15:00 | 7 | high | 25 min |
| 16:00 | 4 | moderate | 30 min |
| 17:00 | 2 | low | 45 min |
| 18:00 | 1 | low | 45 min |
| 19:00 | 1 | low | 45 min |
Throughout the year, the UV Index exhibits significant seasonal variations, peaking during the summer months of May to August, where it reaches extremes of 11 to 12. The highest risk occurs in May, June, and July, with burn times as short as 10 minutes under these conditions. March and April also present considerable UV exposure, categorized as very high, with burn times of just 15 minutes. Visitors and residents should exercise caution from late winter through summer, especially during these high-risk months, by seeking shade, wearing protective clothing, and applying broad-spectrum sunscreen regularly to minimize the risk of skin damage. As the season transitions into fall and winter, UV levels decrease, offering more moderate exposure from October to December.
UV Risk Categories
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 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 |
| Boulder City | 4 | 6 | 8 | 10 | 11 | 12 | 12 | 11 | 10 | 7 | 5 | 3 |
| Houston UVI | 5 | 8 | 9 | 11 | 11 | 12 | 12 | 11 | 10 | 9 | 7 | 5 |