UV Index in Janesville, United States

Last updated: June 2, 2025

Understanding the UV Index is crucial for residents of Janesville, as it directly impacts sun safety and overall skin health. With peak UV levels often reaching as high as 11 in the early afternoon, awareness of sunlight exposure can help prevent painful sunburns and long-term skin damage. Janesville's robust Dfa climate—characterized by hot summers and chilly winters—means that while sun safety is especially important during warmer months, even moderate UV levels should be approached with caution year-round. Stay informed and protect your skin by checking the UV Index before heading outdoors!

Hourly UV Index in Janesville

The UV Index throughout the day follows a predictable rise and fall, peaking at 11 around 1:00 PM. Starting at a modest 1 at 7:00 AM, it gradually escalates, reaching 10 by 12:00 PM, signaling the need for sun protection. As the afternoon progresses, the index dips from 11 to 8 by 3:00 PM, then declines further to 2 by 6:00 PM, and finally settles back at 1 by 7:00 PM. This data underscores the importance of taking precautions during the hours of peak UV exposure, particularly between 11:00 AM and 3:00 PM, when levels are highest and pose the greatest risk to skin health.

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.
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	11	extreme	10 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

Monthly UV Index Trends in Janesville

Throughout the year, the UV Index demonstrates significant seasonal fluctuations, with high-risk months typically occurring from April to September. In April, the UV Index escalates to 8, indicating very high exposure risks, and remains elevated through May (9) and June (11), where it reaches an extreme level. July (10) and August (9) continue to present very high risks, before tapering off in September (8). As a precaution, visitors and residents should take protective measures, especially during these peak months, by seeking shade, wearing protective clothing, and applying sunscreen frequently. In contrast, the UV Index drops to a moderate level (3-5) from October to March, allowing for safer outdoor activities during this period.

Monthly Maximum UV Index for Janesville, United States

The monthly maximum UV Index (UVI) represents the highest UV radiation level recorded each month in Janesville. It measures the strength of ultraviolet radiation from the sun and helps assess the risk of sunburn and UV-related health issues.

Data source: Statistical UV Index data for Janesville, 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 Janesville UV Index with Other United States Cities

The table above highlights how UV exposure in Janesville 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.

Janesville's solar exposure compared to other cities in United States. Generated using Copernicus Atmosphere Monitoring Service information.
	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Janesville	3	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