Last updated: August 1, 2025
Understanding the UV Index is crucial for residents of Collinsville, United States, where the warm Cfa climate brings varying levels of sun exposure throughout the year. By monitoring UV levels, you can effectively protect your skin from harmful effects like sunburn and long-term damage. With peak UV levels reaching 10 during midday, it’s essential to be aware of when to seek shade and apply sunscreen. In a region where summer days may invite outdoor activities, knowing the UV Index helps ensure you enjoy the sun safely.
During the day, the UV Index fluctuates, providing a clear picture of sunlight intensity. Morning hours see a gentle rise, with values peaking at 1 from 7:00 AM to 8:00 AM, making it a safe time for outdoor activities. However, as the sun climbs higher, the index sharply escalates, hitting 3 by 9:00 AM and jumping to an intense 7 by 11:00 AM. The hottest moment arrives at 1:00 PM and 2:00 PM, where it reaches a peak of 10, indicating a high risk of harm from unprotected sun exposure. The intensity begins to wane in the afternoon, dipping to 6 at 4:00 PM and gradually descending to 1 by 7:00 PM, suggesting that early morning and late evening are the most favorable times to bask in the sun safely.
| 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 | 8 | 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 experiences significant seasonal changes, with the highest levels occurring from March to October. The high-risk months are typically March, April, May, June, July, August, September, and October, when the index reaches very high to extreme levels. Specifically, June presents the greatest risk with a UV Index of 11, indicating extreme exposure and a burn time of only 10 minutes. During these months, it is crucial for both visitors and residents to take proper precautions, including wearing sunscreen, protective clothing, and sunglasses, and seeking shade during peak hours (10 a.m. to 4 p.m.). In contrast, the months of January, February, November, and December have a moderate exposure category, allowing for longer burn times of 30 minutes. Awareness of these fluctuations can help everyone enjoy outdoor activities safely.
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 |
| Collinsville | 3 | 6 | 8 | 9 | 10 | 11 | 10 | 10 | 9 | 8 | 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 |