Last updated: July 2, 2025
Understanding the UV Index is crucial for residents of Greenville, United States, as it helps foster awareness about the potential harm caused by ultraviolet radiation. Elevated UV levels can lead to sunburn, increase the risk of skin cancer, and damage skin health over time. With Greenville's humid subtropical climate, sunshine and high UV exposure, especially during midday hours, can pose significant risks to skin safety. By staying informed about the daily UV Index, you can better protect yourself and your loved ones from the sun's harmful effects while enjoying the great outdoors.
The UV Index starts off gentle in the early hours, peaking at 1 around 07:00 and 08:00. As the sun ascends, it gradually climbs to reach 2 by 09:00 and then surges to 4 by 10:00. A significant spike occurs around 11:00, peaking at 6, before reaching its zenith of 10 from 13:00 to 14:00—a crucial time for sun protection. As the afternoon wanes, the index begins to decline, tapering down to 7 at 16:00, then to 5 by 17:00. As the sun sets, it drops to 3 at 18:00, and finally sinks back to a safe 1 by 19:00, reminding us to be cautious in the midday sun while enjoying the warm daylight.
| 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 | 6 | 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 | 5 | moderate | 30 min |
| 18:00 | 3 | moderate | 30 min |
| 19:00 | 1 | low | 45 min |
The UV Index displays significant seasonal fluctuations, with higher levels typically peaking during the summer months. From March to September, UV levels reach high to extreme categories, particularly from April to June, where the Index hits a maximum of 11 in June. This indicates heightened risks for sunburn, with burn times decreasing to as little as 10 minutes during the most intense months. April to August marks the high-risk period, where residents and visitors are strongly advised to adopt protective measures such as wearing sunscreen, hats, and UV-blocking sunglasses, and seeking shade during peak sun hours. In contrast, the fall and winter months of October to February witness lower UV exposure, making sun protection less urgent but still necessary during midday hours, as UV Index levels remain moderate to high.
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 |
| Greenville | 3 | 5 | 7 | 10 | 10 | 11 | 10 | 10 | 8 | 6 | 4 | 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 |