Last updated: June 2, 2025
Understanding the UV Index is crucial for residents and visitors of Sullivans Island, where the warm, humid climate of the Cfa zone brings heightened sun exposure. With peak UV levels reaching as high as 11 during midday hours, being aware of these levels is essential for preventing sunburn and maintaining long-term skin health. As the sun rises, so does the risk of UV-related harm, making it vital to stay informed and take precautions, especially when enjoying the beautiful beaches and outdoor activities the island has to offer.
At sunrise, the UV Index begins its ascent, peaking at 1 by 07:00. As the day progresses, it rises steadily, hitting 2 by 08:00 and reaching a moderate 3 by 09:00. The intensity ramps up significantly from 10:00, where it soars to 6, and then it continues its climb to a striking 10 at 12:00. The highest point arrives at 13:00 and 14:00, where the UV Index maxes out at 11, signaling a time when sun protection is crucial. As the afternoon wanes, the index gradually decreases, settling at 9 by 15:00. By late afternoon, the values dip to 4 at 17:00, and then cool down to 2 by 18:00, before fading to 1 by 19:00 as daylight fades. It's a clear reminder to stay protected during the sunniest hours!
| 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 | 6 | high | 25 min |
| 11:00 | 8 | very high | 15 min |
| 12:00 | 10 | very high | 15 min |
| 13:00 | 11 | extreme | 10 min |
| 14:00 | 11 | extreme | 10 min |
| 15:00 | 9 | very high | 15 min |
| 16:00 | 7 | high | 25 min |
| 17:00 | 4 | moderate | 30 min |
| 18:00 | 2 | low | 45 min |
| 19:00 | 1 | low | 45 min |
As the seasons change, so do UV levels, with significant increases from February to August. Notably, March to August are high-risk months, peaking in July with a UV Index of 12, categorized as extreme and a burn time of only 10 minutes. Visitors and residents should exercise increased caution during these months, seeking shade, wearing protective clothing, and applying sunscreen regularly. In contrast, winter months like January and December see a moderate UV Index of 4, allowing for more relaxed outdoor activities. However, November still poses a high risk with a UV Index of 6, reminding all to remain vigilant regardless of the season.
UV Risk Categories
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 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 |
| Sullivans Island | 4 | 7 | 9 | 10 | 11 | 11 | 12 | 11 | 9 | 8 | 6 | 4 |
| Houston UVI | 5 | 8 | 9 | 11 | 11 | 12 | 12 | 11 | 10 | 9 | 7 | 5 |