Last updated: July 2, 2025
Understanding the UV Index is essential for residents of Ontonagon, Michigan, as it plays a crucial role in protecting your skin health and preventing sunburn. With the region's Dfb climate, the sun's rays can pose increased risks during the warmer months, especially around midday when UV levels peak significantly. By staying informed about daily UV fluctuations, especially when values soar above 5, you can take proactive steps to shield yourself and your loved ones from potential harm. Embrace the beautiful outdoors while ensuring you enjoy the sunshine safely!
The UV Index for the day reflects a dynamic rise in solar intensity as we move toward midday, peaking at 9 between 1:00 PM and 2:00 PM. Starting off gently, the day begins with a low UV rate of 1 at both 7:00 AM and 8:00 AM, making it safe for early morning activities. As the sun climbs higher, we see a steady increase, hitting 4 by 10:00 AM and reaching 5 at 11:00 AM. By noon, the UV Index escalates to 7, signaling that sun protection is becoming increasingly crucial. Post-peak hours show a gradual decline, with readings at 8 and 7 for 3:00 PM and 4:00 PM, respectively, before tapering off to a more moderate 2 by 7:00 PM. Therefore, it’s essential to stay vigilant during peak hours to safeguard against harmful UV exposure!
| 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 | 9 | very high | 15 min |
| 14:00 | 9 | very high | 15 min |
| 15:00 | 8 | very high | 15 min |
| 16:00 | 7 | high | 25 min |
| 17:00 | 5 | moderate | 30 min |
| 18:00 | 3 | moderate | 30 min |
| 19:00 | 2 | low | 45 min |
Throughout the year, the UV Index experiences notable seasonal changes, with significant increases from late winter into summer. January sees a low UV Index of 2, indicating minimal risk, while February and March rise to 4 and 5, respectively, where exposure becomes moderate. April marks the onset of high-risk periods with a UV Index of 7, peaking in May and June at 8 and 9, categorized as very high. This trend continues into July and August, where protective measures are essential due to the same high values of 9 and 8. By September, the UV Index decreases to 7, signaling a return to high risk but gradually moderating through October (5) and November (3) before dropping back to low levels in December. Visitors and residents are strongly advised to prioritize sun protection during the months of May through September, when the potential for skin damage is greatest, using protective clothing, sunscreen, and seeking shade during peak hours.
UV Risk Categories
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Ontonagon | 2 | 4 | 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 |