Last updated: July 2, 2025
Understanding the UV Index is crucial for residents and visitors of Sun Valley, United States, where the sun-soaked climate can lead to elevated risks of UV radiation exposure. Recognizing varying UV levels throughout the day is essential for sunburn prevention and maintaining overall skin health. During peak hours, particularly between 11 AM and 2 PM, the UV Index can reach dangerously high levels of 10-11, highlighting the need for protective measures. As this Dsc climate zone offers plenty of sunshine, it's important to stay informed about the UV Index to enjoy the outdoors safely and protect your skin from harmful rays.
As the sun rises, the UV Index starts off low at 1 by 07:00, making it a safe time for outdoor activities. By 09:00, it rises to 3, signaling increasing sunlight. The real surge hits at 10:00 with a 5, reaching 8 by 11:00—a clear indication that sun protection is becoming necessary. The peak intensity arrives at 12:00, reaching a scorching 10, and continues to soar to an intense 11 from 13:00 to 14:00. As the afternoon rolls in, the index begins to dip slightly to 10 by 15:00, and further declines to 8 by 16:00. Finally, as the day unwinds, the UV levels decrease to 5 at 17:00, then settle at 3 and 2 by 18:00 and 19:00, respectively. Stay sun-smart during those peak hours to protect your skin!
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 1 | low | 45 min |
| 08:00 | 1 | low | 45 min |
| 09:00 | 3 | moderate | 30 min |
| 10:00 | 5 | moderate | 30 min |
| 11:00 | 8 | very high | 15 min |
| 12:00 | 10 | very high | 15 min |
| 13:00 | 11 | extreme | 10 min |
| 14:00 | 11 | extreme | 10 min |
| 15:00 | 10 | very high | 15 min |
| 16:00 | 8 | very high | 15 min |
| 17:00 | 5 | moderate | 30 min |
| 18:00 | 3 | moderate | 30 min |
| 19:00 | 2 | low | 45 min |
Throughout the year, UV levels fluctuate significantly, with March through September marked as high-risk months. During this period, the UV Index peaks, reaching an extreme level of 11 or higher in May, June, and July, where even brief exposure can lead to burns in just 10 minutes. The earlier spring months of March and April present a very high risk as well, requiring caution with a burn time of only 15 minutes. Conversely, the winter months of January, February, November, and December feature a moderate UV Index (3-5) with safer burn times of 30 minutes or more. To ensure safety, visitors and residents are advised to wear sunscreen, protective clothing, and seek shade during peak UV hours, especially from late spring to late summer.
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 |
| Sun Valley | 3 | 5 | 8 | 9 | 11 | 12 | 11 | 10 | 9 | 6 | 4 | 3 |
| 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 |