UV Index in St. Charles, United States

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.

Hourly UV Index in St. Charles

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.

Average solar exposure data for the current time of the year. Actual values may vary and depend on many factors, such as cloud cover, vegetation cover, surface type, etc.
TimeUVICategoryTime to Burn
07:001low45 min
08:002low45 min
09:004moderate30 min
10:006high25 min
11:008very high15 min
12:0010very high15 min
13:0010very high15 min
14:009very high15 min
15:008very high15 min
16:005moderate30 min
17:003moderate30 min
18:002low45 min
19:001low45 min

Monthly UV Index Trends in St. Charles

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.

Monthly Maximum UV Index for St. Charles, United States

The monthly maximum UV Index (UVI) represents the highest UV radiation level recorded each month in St. Charles. It measures the strength of ultraviolet radiation from the sun and helps assess the risk of sunburn and UV-related health issues.
JanFebMarAprMayJunJulAugSepOctNovDec34689101098532
Data source: Statistical UV Index data for St. Charles, based on information from the Copernicus Climate Change Service.

UV Risk Categories

  •  Extreme (11+): Avoid the sun, stay in shade.
  •  Very High (8-10): Limit sun exposure.
  •  High (6-7): Use SPF 30+ and protective clothing.
  •  Moderate (3-5): Midday shade recommended.
  •  Low (0-2): No protection needed.

Compare St. Charles UV Index with Other United States Cities

The table above highlights how UV exposure in St. Charles compares to other major locations across United States. This comparison helps travelers and residents better understand regional sun intensity and plan outdoor activities with sun safety in mind.
St. Charles's solar exposure compared to other cities in United States. Generated using Copernicus Atmosphere Monitoring Service information.
 JanFebMarAprMayJunJulAugSepOctNovDec
St. Charles34689101098632
Chicago UVI34689101098642
Brooklyn UVI35681010998642
New York City UVI35681010998642
Los Angeles UVI46891011111010754
Houston UVI589111112121110975