Last updated: July 2, 2025
Understanding the UV Index in Jefferson, United States is crucial for residents and visitors alike, as it provides essential information about the sun's ultraviolet radiation levels throughout the day. Awareness of UV levels is vital for preventing sunburn and maintaining skin health, particularly during peak exposure times when indices can soar to dangerous levels—like the midday peak of 11. Located in a humid subtropical climate (Cfa), Jefferson experiences varying UV exposure risks, making it important to stay informed and take necessary precautions to enjoy the sun safely.
As the day unfolds, the UV Index ramps up rapidly, starting from a gentle 1 at 7:00 AM and gradually climbing to reach a peak of 11 by 1:00 PM and 2:00 PM. This hour marks the height of sun exposure, where the risk of harm from unprotected sun exposure is significant. After this peak, the index begins to descend, dropping to 9 by 3:00 PM, then tapering off to 6 at 4:00 PM, and finally settling back to a mild 1 by 7:00 PM. For those planning outdoor activities, early afternoon is best approached with caution and protection—a reminder that while the sun can be enjoyable, it demands respect!
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 1 | low | 45 min |
| 08:00 | 1 | low | 45 min |
| 09:00 | 3 | moderate | 30 min |
| 10:00 | 5 | moderate | 30 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 |