Last updated: May 3, 2025
Understanding the UV Index is crucial for residents and visitors in Ketchum, Idaho, where the breathtaking mountain views come with a heightened risk of UV exposure. With the region's high-altitude climate, the sun's rays can be more intense, making awareness of daily UV levels essential for sunburn prevention and long-term skin health. From the relatively mild exposure in the morning to peak levels around noon, knowing when to seek shade or apply sunscreen can protect your skin and enhance your outdoor experiences in this beautiful locale. Stay informed and enjoy all that Ketchum has to offer while safeguarding your skin!
The UV Index throughout the day presents a striking pattern that underscores the importance of sun protection. Starting from a modest 1 at 07:00, the index gradually climbs, reaching 2 by 08:00. A noticeable rise occurs as the day progresses, peaking at a blistering 11 between 13:00 and 14:00—the critical hours when UV exposure is at its highest. After this zenith, the index gracefully tapers down, showcasing 10 at 15:00, followed by a decline to 5 by 17:00. As evening approaches, values drop dramatically to 3 by 18:00, and finally, the day concludes with a safe 1 at 19:00. This data clearly highlights the importance of taking precautions during peak hours to safeguard against harmful UV rays.
| 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 | 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 | 1 | 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 |
| Ketchum | 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 |