Last updated: June 2, 2025
Understanding the UV Index is crucial for the residents of Alton, United States. With its Dfa climate, Alton experiences varied sunshine levels that can significantly impact skin health. Awareness of UV levels not only helps in preventing sunburn but also plays a vital role in long-term skin protection. From the peak index of 11 around midday to the lower values in the morning and evening, knowing when to seek shade or apply sunscreen can make all the difference. Protect yourself while enjoying the wonderful outdoor opportunities Alton has to offer!
The UV Index throughout the day exhibits a clear and striking progression. Starting off at a gentle 1 at 07:00, the intensity gradually climbs as the sun rises. By 09:00, it reaches 3, but the real surge hits at 10:00, peaking at an impressive 11 around 13:00—a crucial time for sun safety. The index begins to taper off after this zenith, with values declining to 5 by 17:00 and dipping further to 1 as the day winds down at 19:00. This data highlights the importance of taking protective measures during the midday hours when UV exposure is at its highest.
| 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 | 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 exhibits significant seasonal fluctuations, with high-risk months generally occurring from April through September. During these months, the UV Index peaks, reaching an extreme level of 11 in June, where exposure should be limited to just 10 minutes to avoid sunburn. The remainder of the summer, particularly in July and August, also presents very high levels, suggesting burn times of only 15 minutes. Conversely, the winter months, particularly January and December, feature lower indices of 2 and 3, respectively, meaning sun exposure is less hazardous, allowing for burns in approximately 45 minutes. Residents and visitors are strongly advised to take necessary precautions during higher UV Index months, including wearing sunscreen, protective clothing, and seeking shade, especially between 11 a.m. and 3 p.m., when the sun is at its most intense. As the seasons change, adjusting sun safety practices is essential for safeguarding skin health.
UV Risk Categories
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Alton | 2 | 5 | 5 | 8 | 9 | 11 | 10 | 9 | 8 | 5 | 3 | 3 |
| 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 |