Last updated: August 1, 2025
Understanding the UV Index is crucial for residents and visitors of Boulder City, United States, where the climate is characterized as BWh, featuring hot, dry summers. As the sun’s rays can intensify quickly, especially during peak hours, being aware of UV levels helps in preventing sunburn and protecting your skin's overall health. With maximum UV Index readings soaring as high as 12 during midday, it's vital to take necessary precautions to mitigate risks associated with excessive sun exposure. By staying informed, you can enjoy the stunning outdoor beauty of Boulder City while keeping your skin safe and healthy.
The UV Index fluctuates throughout the day, painting a vivid picture of solar intensity. Starting from a gentle 1 at 07:00, the sun steadily rises, and by 08:00, it reaches a moderate 3. The real heat kicks in around 09:00, hitting 5, and by 10:00, it surges to 8, signaling a call to protect your skin. The peak intensity occurs at 12:00 and 13:00, where it climbs to a striking 12, highlighting the need for sunscreen and shade. As the afternoon progresses, the levels begin to decline, dropping to 11 by 14:00, then tapering off to 8 at 15:00, before easing back to 5 at 16:00. As the day dims, the UV Index falls to 3 by 17:00 and settles back to 1 by 18:00 and 19:00. Stay sun-smart during these peak hours to enjoy the outdoors safely!
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 1 | low | 45 min |
| 08:00 | 2 | low | 45 min |
| 09:00 | 4 | moderate | 30 min |
| 10:00 | 7 | high | 25 min |
| 11:00 | 9 | very high | 15 min |
| 12:00 | 10 | very high | 15 min |
| 13:00 | 11 | extreme | 10 min |
| 14:00 | 9 | very high | 15 min |
| 15:00 | 7 | high | 25 min |
| 16:00 | 5 | moderate | 30 min |
| 17:00 | 3 | moderate | 30 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 |