Last updated: July 2, 2025
In St. Charles, United States, staying informed about the UV Index is crucial for safeguarding your skin and overall health. With peak UV levels reaching as high as 10 during the midday hours, understanding these readings is essential for preventing sunburn and minimizing long-term skin damage. The city's Dfa climate zone contributes to varied UV exposure risks throughout the year, making it important for residents and visitors alike to be aware of their surroundings. By keeping track of the UV Index, you can enjoy the sun safely while protecting your skin from its harmful effects.
The UV Index throughout the day showcases a dynamic pattern of sun exposure, peaking during the afternoon. At 07:00, the index starts low at 1, gradually increasing as the sun rises. By 10:00, it reaches 6, signaling a rise in sun intensity, culminating in a striking 10 from 12:00 to 13:00, indicating a high risk of harm from unprotected sun exposure. As the day progresses, the UV Index declines, dropping to 3 by 17:00, and steadily returning to 1 by 19:00. This data highlights the importance of sun protection, especially during midday when the UV Index is at its highest.
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 | 10 | very high | 15 min |
13:00 | 10 | very high | 15 min |
14:00 | 9 | very high | 15 min |
15:00 | 8 | very high | 15 min |
16:00 | 5 | moderate | 30 min |
17:00 | 3 | moderate | 30 min |
18:00 | 2 | low | 45 min |
19:00 | 1 | low | 45 min |
Throughout the year, UV exposure varies significantly, with notable peaks between March and October. The high-risk months are April to August, where the UV Index consistently reaches very high levels of 8 to 10 and the burn time reduces to just 15 minutes. In contrast, the low-risk months of November and December see UV Index values fall to 3 and 2, respectively, allowing for safe exposure times of up to 30 and 45 minutes. Residents and visitors are advised to take extra precautions during the high-risk months by seeking shade, wearing protective clothing, and applying sunscreen regularly to mitigate the increased risk of sunburn and skin damage.
UV Risk Categories
Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
---|---|---|---|---|---|---|---|---|---|---|---|---|
St. Charles | 3 | 4 | 6 | 8 | 9 | 10 | 10 | 9 | 8 | 6 | 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 |