Last updated: May 3, 2025
Understanding the UV Index is essential for residents of Grand Rapids, where the Dfb climate—characterized by distinct seasons—can significantly influence sun exposure throughout the year. As UV levels can soar to an alarming 8 during midday, being aware of these readings is crucial for preventing sunburn and protecting skin health. With its sunny summers and elevated UV risks, knowing the UV Index empowers you to make informed decisions about outdoor activities, ensuring that you enjoy the beautiful Michigan outdoors while safeguarding your skin against harmful UV rays.
The UV index throughout the day reveals a fascinating pattern of sun intensity. Early risers will notice a gentle start at 1 around 7:00 AM, gradually climbing to a moderate 3 by 9:00 AM. As the sun reaches its peak, the index hits 6 at 11:00 AM, escalating to an impressive 8 from 12:00 PM to 2:00 PM—the height of solar exposure. After this, the UV levels begin to wane, dropping to 7 at 3:00 PM, and further decreasing to moderate numbers of 5, 3, and 2 as the sun sets, concluding the day with a calm 1 at 7:00 PM. Remember, during the peak hours, sun safety is crucial!
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 1 | low | 45 min |
| 08:00 | 2 | low | 45 min |
| 09:00 | 3 | moderate | 30 min |
| 10:00 | 5 | moderate | 30 min |
| 11:00 | 6 | high | 25 min |
| 12:00 | 8 | very high | 15 min |
| 13:00 | 8 | very high | 15 min |
| 14:00 | 8 | very high | 15 min |
| 15:00 | 7 | high | 25 min |
| 16:00 | 5 | moderate | 30 min |
| 17:00 | 3 | moderate | 30 min |
| 18:00 | 2 | low | 45 min |
| 19:00 | 1 | low | 45 min |
Throughout the year, the UV Index experiences significant seasonal changes, impacting sun exposure and burn times. January and December see low UV levels (Index 2), with burn times of 45 minutes, while February and November moderate (Index 3), reducing burn time to 30 minutes. As spring arrives, March (Index 5) indicates a moderate risk before transitioning to April's high level (Index 7) with a burn time of 25 minutes. The peak risk occurs in May and June, where the UV Index reaches 8 to 9, categorizing exposure as very high and necessitating protective measures within just 15 minutes of sun exposure. July continues this trend, while August sees a slight decrease to 8. The UV Index tapers off in September (Index 7), October (Index 5), and November (Index 3), before returning to low levels in December. Visitors and residents are advised to take extra precautions during May through August, including wearing protective clothing, applying sunscreen, and seeking shade during peak hours to minimize the risk of UV exposure.
UV Risk Categories
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Grand Rapids | 2 | 3 | 5 | 7 | 8 | 9 | 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 |