Last updated: May 3, 2025
Understanding the UV Index is crucial for residents and visitors of Alta, United States, where even moderate sun exposure can pose risks to skin health. With the highest UV levels reaching 11 around noon, awareness of UV fluctuations can help prevent sunburn and long-term skin damage. Alta, located in a Csb climate zone, experiences unique weather patterns that contribute to sunlight intensity, making it essential for everyone to stay informed about daily UV levels. By knowing when to seek shade or apply sunscreen, you can enjoy the beautiful outdoors while safeguarding your skin.
The UV Index steadily climbs as the day progresses, starting from a mild 1 at 7:00 AM and reaching a peak of 11 by 1:00 PM. Sun-seekers and outdoor enthusiasts should be mindful, as the index hits a high of 10 at 12:00 PM, signaling significant UV exposure. After this peak, the index gradually decreases, dropping to 8 by 3:00 PM, and continuing to decline to 1 by 7:00 PM. For safe sun enjoyment, it’s best to take precautions during those high UV hours, particularly between 11:00 AM and 2:00 PM. Remember to sport your hats and sunscreen!
| 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 | 6 | 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 | 10 | very high | 15 min |
| 15:00 | 8 | very high | 15 min |
| 16:00 | 6 | high | 25 min |
| 17:00 | 3 | moderate | 30 min |
| 18:00 | 2 | low | 45 min |
| 19:00 | 1 | low | 45 min |
The UV Index exhibits significant seasonal variation, with high-risk months typically occurring from March to August. During this period, peak UV Index values reach 11 in May and June, categorizing these months as extreme, where sensitive individuals can burn in just 10 minutes. March and April see very high levels (UV Index 8 and 9), reducing safe exposure times to 15 minutes. As summer transitions to fall, September and October remain relatively high at 9 and 7, respectively, allowing for burn times of 15 and 25 minutes. Conversely, the winter months of January, February, November, and December report moderate levels (UV Index 3 to 5), with burn times of 30 minutes. Visitors and residents should take these variations into account, especially during high-risk months; protection against UV exposure—such as wearing sunscreen, hats, and protective clothing—is strongly recommended to minimize skin damage.
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 |
| Alta | 3 | 5 | 8 | 9 | 11 | 12 | 11 | 10 | 9 | 7 | 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 |