UV Index in Joliet, United States

Last updated: June 2, 2025

Understanding the UV Index is crucial for residents of Joliet, where the climate falls under the Dfa zone, bringing both warmth and abundant sunshine. High UV levels, peaking around midday with an index of 10, highlight the importance of being vigilant about sun exposure. Recognizing these levels is essential not only for preventing sunburn but also for protecting your long-term skin health. With a typical summer day presenting significant UV risks, staying informed can help you enjoy the beautiful Joliet weather while keeping your skin safe!

Hourly UV Index in Joliet

At dawn, the UV Index starts off gently at 1 by 7:00 AM, barely warranting sun protection. As the morning unfolds, it gradually climbs to 2 by 8:00 AM and reaches 4 at 9:00 AM, signaling moderate exposure risk. The sun peaks at noon with a maximum of 10, indicating high risk for harm from unprotected sun exposure. From 1:00 PM to 2:00 PM, the UV Index holds steady at 10, urging everyone to stay mindful of their sun safety. As the afternoon progresses, the levels decline, dipping to 9 at 2:00 PM and falling further to 5 by 4:00 PM. By evening, the index reduces to 1 by 7:00 PM, allowing for a safe outdoor experience as daylight dims. It’s clear that the midday hours require vigilance against sun exposure, while early and late hours provide a more relaxed approach.

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
11:009very 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 Joliet

Throughout the year, UV index levels fluctuate significantly, with notable increases during the warmer months. January and February experience a moderate UV index of 3 and 4, allowing for a 30-minute burn time under the sun. As the seasons transition into March and onward, the risk escalates, peaking in June and July with a maximum UV index of 10—classifying these months as high-risk. During these summer months, individuals are advised to limit sun exposure to just 15 minutes to prevent skin damage. The trend continues with August and September maintaining high levels (UV index of 9 and 8 respectively) before tapering off in October (UV index 6) and returning to moderate levels in November and December (UV index of 4 and 2). Residents and visitors should prioritize sun protection, especially during the peak months of April through September.

Monthly Maximum UV Index for Joliet, United States

The monthly maximum UV Index (UVI) represents the highest UV radiation level recorded each month in Joliet. It measures the strength of ultraviolet radiation from the sun and helps assess the risk of sunburn and UV-related health issues.
JanFebMarAprMayJunJulAugSepOctNovDec34689101098642
Data source: Statistical UV Index data for Joliet, 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 Joliet UV Index with Other United States Cities

The table above highlights how UV exposure in Joliet 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.
Joliet's solar exposure compared to other cities in United States. Generated using Copernicus Atmosphere Monitoring Service information.
 JanFebMarAprMayJunJulAugSepOctNovDec
Chicago UVI34689101098642
Brooklyn UVI35681010998642
New York City UVI35681010998642
Joliet34689101098642
Los Angeles UVI46891011111010754
Houston UVI589111112121110975