Last updated: July 2, 2025
In Rochester Hills, United States, understanding the UV Index is crucial for maintaining healthy skin and preventing sunburn, especially during the warmer months. As a city situated in a Dfb climate zone, residents often experience varying levels of UV exposure, peaking at values of 10 during midday hours. This stark increase emphasizes the importance of being aware of UV levels to protect against the harmful effects of sun exposure. By staying informed about the daily UV Index, you can enjoy the outdoors while safeguarding your skin health and preventing long-term damage.
The UV Index throughout the day presents a dynamic picture of sun intensity. Starting off gently, the morning hours at 07:00 and 08:00 register a low index of 1, perfect for early risers. As the sun climbs higher, the UV index rises sharply, hitting 4 by 10:00 and peaking at a striking 10 between 13:00 and 14:00—an indicator of potential harm to unprotected skin. After this zenith, the UV levels begin to gracefully descend, settling back to 4 by 17:00 and tapering down to 1 again by 19:00. It’s a vivid reminder that while midday sun can be inviting, protection is essential 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 | 8 | very high | 15 min |
| 16:00 | 7 | high | 25 min |
| 17:00 | 4 | moderate | 30 min |
| 18:00 | 3 | moderate | 30 min |
| 19:00 | 1 | low | 45 min |
Throughout the year, the UV Index varies significantly, reflecting seasonal changes in sun exposure and risk. January and December feature low UV levels (index of 2), with burn times of 45 minutes, providing a safer window for outdoor activities. However, as we transition into February and March, the index rises to moderate levels (4 and 5), shortening burn times to 30 minutes. The arrival of April marks the beginning of high-risk months, peaking in June and July when the UV Index reaches a critical 10, indicating very high exposure risks and necessitating protective measures with burn times of just 15 minutes. August remains similarly high with an index of 9, but the risk begins to decrease in September (UV index 7) and continues to diminish towards October and November. Residents and visitors are advised to prioritize sun safety during the spring and summer months; apply broad-spectrum sunscreen, wear protective clothing, and seek shade during peak hours, especially from April to August.
UV Risk Categories
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Rochester Hills | 2 | 4 | 5 | 8 | 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 |