Last updated: June 2, 2025
Understanding the UV Index is crucial for maintaining skin health in Charleston, where sunny days are a staple of the Cfa climate. The UV Index measures the strength of ultraviolet radiation, which can lead to sunburn and long-term skin damage if proper precautions aren’t taken. With peak UV levels reaching as high as 10 during midday hours, it’s essential for residents and visitors to be aware of these fluctuations and the potential risks they pose. By keeping an eye on the UV Index, you can enjoy the beautiful Charleston sunshine while effectively protecting your skin from harmful effects.
The UV Index data for the day reveals a notable rise in solar intensity, peaking at 10 between 1:00 PM and 2:00 PM. Starting from a gentle 1 at 7:00 AM, the index steadily climbs as the sun ascends, reaching a moderate 5 by 10:00 AM, and then surging to 9 at 12:00 PM. As the clock strikes 1:00 PM, the maximum UV Index of 10 alerts outdoor enthusiasts to take precautions. After this peak, a gradual decline begins, dropping to 4 by 5:00 PM, and the day winds down with readings back to 1 by 7:00 PM. Monitoring these fluctuations is essential for enjoying the sunshine safely!
| 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 | 7 | high | 25 min |
| 12:00 | 9 | 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 | 4 | moderate | 30 min |
| 18:00 | 2 | low | 45 min |
| 19:00 | 1 | low | 45 min |
Throughout the year, UV exposure varies significantly, with the high-risk months spanning from April to September. During this period, the UV Index reaches very high levels, peaking at 10 in May, June, July, and August, where the burn time is as short as 15 minutes. In contrast, January, February, November, and December present moderate risk with an Index of 3 to 5, allowing up to 30 minutes of safe sun exposure. Residents and visitors should take precautions during the spring and summer months, including wearing protective clothing, using sunscreen with high SPF, and seeking shade during peak hours to minimize the risk of sunburn and long-term skin damage. Remember, even on cloudy days, UV rays can still penetrate, so remain vigilant year-round.
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 |
| Charleston | 3 | 5 | 7 | 9 | 10 | 10 | 10 | 10 | 8 | 7 | 5 | 3 |
| 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 |