UV Index in Waterloo, United States

Last updated: July 2, 2025

Understanding the UV Index in Waterloo, United States is essential for anyone who enjoys the great outdoors. With the potential for high UV levels, especially during sunny days, being aware of these environmental factors is crucial for preventing sunburn and maintaining skin health. Waterloo's Csa climate, characterized by warm summers, presents unique challenges, particularly during peak hours when the UV Index can soar to a maximum of 11 around noon. This guide will help you stay informed and protected as you navigate your time under the sun.

Hourly UV Index in Waterloo

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 Waterloo

As the seasons change, so does the UV Index, significantly impacting the risk of sunburn and the need for sun protection. The months of March through August see the highest UV levels, with March and April peaking at an index of 8, while May and June reach an extreme level of 11. Visitors and residents should be particularly cautious during June and July, when burn times drop to just 10 minutes at the extreme index. As we transition into fall, the UV intensity declines, with October still presenting a high index of 6, but moving to a moderate risk by November and December. It is advisable for everyone to wear protective clothing, seek shade, and use sunscreen during these high-risk months to minimize the risk of UV-related health issues.

Monthly Maximum UV Index for Waterloo, United States

The monthly maximum UV Index (UVI) represents the highest UV radiation level recorded each month in Waterloo. 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 Waterloo, 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 Waterloo UV Index with Other United States Cities

The table above highlights how UV exposure in Waterloo 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.

Waterloo'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
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
Waterloo	3	5	8	8	10	11	11	10	9	6	4	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