Last updated: July 2, 2025
In Sierra Vista, Arizona, understanding the UV Index is crucial for maintaining skin health and preventing sunburn. With its semi-arid climate (BSk), residents and visitors are regularly exposed to high levels of ultraviolet radiation, particularly during the peak hours between 10 AM and 2 PM when UV Index values soar to 12, signaling extreme risk. Being aware of these levels allows you to take protective measures, ensuring that outdoor activities remain enjoyable without compromising your skin’s safety. Stay informed to keep your skin protected from the harmful effects of the sun!
As the sun rises, the UV Index begins its climb, starting at a modest 1 at 07:00 AM. By 08:00 AM, it increases to 3, indicating a slight uptick in UV exposure. The intensity escalates rapidly, peaking at 12 between 12:00 PM and 01:00 PM, suggesting the need for sun protection is at its utmost. The index then begins to decline, dropping to 10 by 02:00 PM and gradually easing to 5 by 04:00 PM. As the day winds down, the UV levels fall back to 1 by 06:00 PM, marking a significant reduction in sun intensity. This hourly data highlights the critical midday hours where caution is essential, as the sun can be particularly harsh. Be sure to enjoy the sunshine while staying protected!
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 1 | low | 45 min |
| 08:00 | 3 | moderate | 30 min |
| 09:00 | 6 | high | 25 min |
| 10:00 | 9 | very high | 15 min |
| 11:00 | 11 | extreme | 10 min |
| 12:00 | 12 | extreme | 10 min |
| 13:00 | 12 | extreme | 10 min |
| 14:00 | 10 | very high | 15 min |
| 15:00 | 8 | very high | 15 min |
| 16:00 | 5 | moderate | 30 min |
| 17:00 | 2 | low | 45 min |
| 18:00 | 1 | low | 45 min |
| 19:00 | 1 | low | 45 min |
The UV Index experiences notable changes throughout the year, with peaks from March to September when the levels reach extreme (10-13), particularly in April and June. The highest risk months are March through September, where the burn time decreases to just 10 minutes during peak exposure. In contrast, January, December, and November present moderate to high exposure levels, allowing for longer burn times of up to 30 minutes. It is crucial for both visitors and residents to remain vigilant during the high-risk months by applying sunscreen, wearing protective clothing, and seeking shade, especially during midday hours when UV radiation is at its strongest.
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 |
| Houston UVI | 5 | 8 | 9 | 11 | 11 | 12 | 12 | 11 | 10 | 9 | 7 | 5 |
| Sierra Vista | 5 | 7 | 10 | 12 | 12 | 13 | 12 | 12 | 11 | 9 | 6 | 5 |