Last updated: June 2, 2025
Understanding the UV Index is crucial for residents of Jefferson, United States, where the climate (Cfa) offers a mix of warm summers and mild winters, resulting in varied UV exposure throughout the year. Being aware of UV levels not only helps in preventing sunburn and protecting your skin health but also empowers you to make informed decisions about outdoor activities. In Jefferson, peak UV Index values can reach as high as 11 around midday, highlighting the need for vigilance against harmful UV rays. By staying informed, you can enjoy the beautiful sunshine while keeping your skin safe!
The UV Index throughout the day presents a clear trajectory of increasing intensity, peaking dramatically as the sun reaches its zenith. At 07:00, the index starts modestly at 1, signifying minimal risk. However, as the hours roll on, from 08:00 to 10:00, it climbs steadily to 6, marking the onset of moderate exposure. The real surge occurs between 11:00 and 13:00, where the index hits a staggering 11, indicating a very high risk for unprotected skin. Even as it begins to taper off in the afternoon—returning to 9 by 15:00 and further down to 4 by 17:00—the day's UV intensity serves as a reminder of the importance of sun protection. By 19:00, it drops back to a safe 1, allowing for a sigh of relief as daylight wanes. Embrace the sun wisely!
| 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 | 6 | high | 25 min |
| 17:00 | 4 | moderate | 30 min |
| 18:00 | 2 | low | 45 min |
| 19:00 | 1 | low | 45 min |
Throughout the year, the UV Index shows significant seasonal changes, particularly peaking during the summer months. From January to February, the UV Index rises from a moderate level of 4 to a high 7, indicating the need for increased sun protection. The months of March through August are notably high-risk, as the UV Index remains in the very high to extreme category, reaching a peak of 11 in May through August, with a burn time of only 10 minutes; therefore, individuals should practice stringent sun safety, including wearing protective clothing and using sunscreen frequently. As we move into September and October, the UV Index decreases but remains a concern, especially in September with a UV of 10. By November and December, the levels drop back to moderate (4) and high (6), allowing for a temporary respite. Visitors and residents should remain vigilant during the high-risk months and adopt protective measures against harmful UV exposure, particularly from March through October.
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 |
| Jefferson | 4 | 7 | 8 | 10 | 11 | 11 | 11 | 11 | 10 | 8 | 6 | 4 |
| Houston UVI | 5 | 8 | 9 | 11 | 11 | 12 | 12 | 11 | 10 | 9 | 7 | 5 |