Last updated: August 1, 2025
Understanding the UV Index is vital for residents of Alpena, Michigan. With its humid continental climate (Dfb), Alpena experiences distinct seasonal variations in UV exposure, making it essential to be vigilant about sun safety. The UV Index informs us about the sun's intensity and helps to prevent harmful effects like sunburn and skin damage. During peak hours, particularly from noon to 3 PM, UV levels can soar up to a risk level of 9, indicating a high potential for harm. Being aware of these fluctuations not only promotes better skin health but also encourages responsible outdoor activities year-round in Alpena.
As the sun rises, the UV Index gradually climbs, starting at a low of 1 by 07:00 and 08:00. The real leap begins at 09:00, where it reaches 3, escalating to 4 by 10:00. As noon approaches, the UV Index peaks at an impressive 9 from 13:00 to 14:00, making it crucial to take protective measures during those hours. Afterward, it begins to taper off, dropping to 6 by 16:00, and further declining through the late afternoon and evening, eventually falling back to 1 by 19:00. For those venturing outdoors, staying vigilant to the UV levels during the midday hours is essential for skin protection!
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 1 | low | 45 min |
| 08:00 | 1 | low | 45 min |
| 09:00 | 2 | low | 45 min |
| 10:00 | 4 | moderate | 30 min |
| 11:00 | 5 | moderate | 30 min |
| 12:00 | 7 | high | 25 min |
| 13:00 | 8 | very high | 15 min |
| 14:00 | 8 | very high | 15 min |
| 15:00 | 7 | high | 25 min |
| 16:00 | 6 | high | 25 min |
| 17:00 | 4 | moderate | 30 min |
| 18:00 | 2 | low | 45 min |
| 19:00 | 1 | low | 45 min |
Throughout the year, the UV Index reveals significant seasonal changes in sun exposure risks. January and December are the safest months, with a low exposure category and burn times of 45 minutes, while February and March indicate a moderate risk with an elevated UV Index of 4 and 5, respectively. The high-risk period peaks from April to August, where the UV Index climbs to very high levels, particularly in June (10) and July (9), warranting a burn time reduction to just 15 minutes. September sees a slight decrease to a high category (UV Index 7) while October through November return to moderate levels. Visitors and residents should take precautions during high-risk months by applying sunscreen, wearing protective clothing, and seeking shade, especially between April and August when the sun's intensity is at its highest.
UV Risk Categories
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Alpena | 2 | 4 | 5 | 7 | 8 | 10 | 9 | 8 | 7 | 5 | 3 | 2 |
| 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 |