Last updated: July 2, 2025
Understanding the UV Index is crucial for residents of Jefferson, United States, where sunny days are common in the humid subtropical climate. As UV levels can soar to a maximum of 10 around midday, awareness of these levels is essential for preventing sunburn and protecting your skin health. With nearly half the day exposing you to moderate to high UV risks, knowing when to seek shade or apply sunscreen can help safeguard both your immediate well-being and long-term health. Stay informed about the UV Index to enjoy the outdoors safely in Jefferson!
The UV Index chart reveals a dynamic daily pattern of solar intensity. Starting early in the day, the UV Index remains low, peaking at 1 by 08:00. However, as the sun reaches its zenith, the index surges dramatically—hitting 7 by 11:00 and soaring to a maximum of 10 between 13:00 and 14:00. This signals a critical window for sun exposure, where protection is essential. As the afternoon progresses, the UV levels begin to decline, dropping to 4 by 17:00, before tapering off to 1 again by evening. To stay safe, it's vital to be cautious during those peak hours!
| 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 | 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 |
| Jefferson | 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 |