Last updated: July 2, 2025
In Ann Arbor, United States, staying informed about the UV Index is crucial for safeguarding your skin health and preventing sunburn. With the region's Dfa climate, residents experience significant seasonal variations that can lead to high UV exposure, particularly during the summer months. Understanding the UV levels—like the peak reading of 10 around midday—empowers you to take proactive measures when the sun is strongest, ensuring you enjoy the outdoors while minimizing risks. Whether you’re lounging in a park or commuting, knowing when to seek shade or apply sunscreen can make all the difference in protecting your skin.
The UV Index reveals a dramatic rise in sun exposure throughout the day, reaching its peak between 1 PM and 2 PM with a striking value of 10. Starting from a low of 1 at 7 AM and 8 AM, the intensity gradually escalates, hitting 4 by 10 AM and then surging to 7 at 11 AM. By noon, the index climbs to 8, and just an hour later, it reaches its maximum. As the afternoon wears on, it begins to taper off, descending to 9 at 3 PM, followed by a steady decline to 5 by 5 PM, and finally returning to 3 by 6 PM and 1 by 7 PM. This data emphasizes the importance of protecting yourself from strong UV rays, particularly 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 | 4 | moderate | 30 min |
| 11:00 | 7 | high | 25 min |
| 12:00 | 8 | very high | 15 min |
| 13:00 | 10 | very high | 15 min |
| 14:00 | 10 | very high | 15 min |
| 15:00 | 9 | very high | 15 min |
| 16:00 | 7 | high | 25 min |
| 17:00 | 5 | moderate | 30 min |
| 18:00 | 3 | moderate | 30 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 |