Last updated: May 3, 2025
Understanding the UV Index is essential for residents of Alton, United States, where the climate falls under the Dfb zone, characterized by warm summers and cold winters. Awareness of UV levels is crucial, especially during peak hours when the index can soar to a dangerous 9 around noon, significantly increasing the risk of sunburn and skin damage. By staying informed about UV exposure, you can take proactive steps to protect your skin health, ensuring enjoyable outdoor activities without the harmful effects of excessive sun exposure. Remember, even on cloudy days, UV rays can still pose a threat, making it vital to check the UV Index regularly!
The UV Index for today presents an intriguing journey through the hours. It starts off gently at 1 at 07:00, but as the morning progresses, it climbs swiftly to 2 by 08:00 and reaches a moderate 4 at 09:00. The sun intensifies its rays further, peaking at a robust 9 between 12:00 and 13:00—a reminder to take precautions against harmful UV exposure. Following this peak, the index gradually descends, dipping to 6 at 15:00, and mellowing down to 1 by 18:00. This pattern highlights the importance of seeking shade or applying sunscreen during the midday hours when UV radiation is most potent.
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 1 | low | 45 min |
| 08:00 | 2 | low | 45 min |
| 09:00 | 4 | moderate | 30 min |
| 10:00 | 6 | high | 25 min |
| 11:00 | 8 | very high | 15 min |
| 12:00 | 9 | very high | 15 min |
| 13:00 | 9 | very high | 15 min |
| 14:00 | 8 | very high | 15 min |
| 15:00 | 6 | high | 25 min |
| 16:00 | 4 | moderate | 30 min |
| 17:00 | 3 | moderate | 30 min |
| 18:00 | 1 | low | 45 min |
| 19:00 | 1 | low | 45 min |
Throughout the year, UV exposure varies significantly, with high-risk months typically from April to August, where the UV Index peaks at levels of 8 to 10, resulting in a very high exposure category and a quick burn time of just 15 minutes. In contrast, the winter months of January, February, and December feature a much lower UV Index, ranging from 2 to 4, which is classified as low to moderate, allowing for longer exposure times of 30 to 45 minutes without significant risk. To protect against harmful UV rays, it’s crucial for visitors and residents alike to use sunscreen, wear protective clothing, and seek shade during the peak sun hours, especially from April to August when sun safety practices should be a top priority.
UV Risk Categories
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Alton | 3 | 4 | 5 | 8 | 9 | 10 | 9 | 9 | 7 | 5 | 3 | 2 |
| 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 |
| Houston UVI | 5 | 8 | 9 | 11 | 11 | 12 | 12 | 11 | 10 | 9 | 7 | 5 |