Last updated: May 3, 2025
Understanding the UV Index in Ann Arbor is crucial for protecting your skin and maintaining overall health. As the sun’s rays can lead to sunburn and long-term skin damage, staying informed about daily UV levels empowers residents to enjoy the outdoors safely. With its humid continental climate, Ann Arbor experiences significant fluctuations in UV exposure throughout the year, emphasizing the need for vigilance, particularly during peak hours. During the sunnier months, UV levels can soar to 9 between noon and 2 PM, making it essential to prioritize sun safety and skin health as you enjoy everything this vibrant city has to offer.
As the sun rises, the UV Index begins at a low 1 at 07:00, providing a gentle start to the day. By 09:00, it picks up to 3, signaling the need for a bit more awareness. The real warmth comes at 10:00, with the index reaching 5, and it escalates quickly as noon approaches. By 12:00, we hit 8, and at 13:00, the UV index peaks at 9, marking the height of solar intensity. As the afternoon progresses, values remain high but start to dip slightly: 8 at 15:00 and then down to 6 by 16:00. As the sun begins to set, the index falls to 4 at 17:00 and finally drops back to 1 by evening, reminding us to bask in the sun wisely and protect our skin during peak hours!
| 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 | 7 | high | 25 min |
| 12:00 | 8 | very high | 15 min |
| 13:00 | 9 | very high | 15 min |
| 14:00 | 9 | very high | 15 min |
| 15:00 | 8 | very high | 15 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 shows significant seasonal changes, impacting the risk of sun exposure. January and December have the lowest UV levels (2), indicating a low risk for sunburn, with burn times of 45 minutes. As spring unfolds, February and March present moderate UV levels (4-5) and shorter burn times of 30 minutes, signaling the need for increased sun protection. The high-risk months commence in April, peaking in June and July with very high UV Index values (9-10) and critical burn times of only 15 minutes; thus, it’s essential for visitors and residents to take protective measures, such as wearing sunscreen, hats, and UV-blocking clothing. August to September gradually sees a decline, but caution remains crucial with a high level of UV (7) in September and a burn time of 25 minutes. In October and November, UV levels moderate again to 4 and 5, respectively, where sun safety should continue to be a priority until levels drop back to low in December. Always consider the UV Index when planning outdoor activities, particularly during the peak summer months.
UV Risk Categories
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Ann Arbor | 2 | 4 | 5 | 9 | 9 | 10 | 10 | 9 | 7 | 5 | 4 | 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 |