UV Index in Thornton, United States

Last updated: July 2, 2025

Understanding the UV Index in Thornton, United States is crucial for maintaining skin health and preventing sunburn, especially given the region's Csa climate. With UV levels soaring to as high as 11 during peak sunlight hours, awareness of UV exposure is essential for outdoor enthusiasts and families alike. By monitoring the UV Index, residents can take proactive steps to shield themselves from harmful rays, ensuring a safer sun experience while embracing the beautiful Colorado outdoors.

Hourly UV Index in Thornton

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 Thornton

The UV Index exhibits significant seasonal variations, with the highest levels occurring from April to August. During this period, the highest risk months are June and July, where the UV Index peaks at 11, categorized as extreme, resulting in a burn time of just 10 minutes. Conversely, January, November, and December show the lowest UV Index levels, categorized as moderate, with a burn time of 30 minutes. To ensure safety, visitors and residents should take precautionary measures during high UV periods, especially by seeking shade, wearing protective clothing, and using sunscreen with high SPF when outdoors, particularly in the late morning to early afternoon hours.

Monthly Maximum UV Index for Thornton, United States

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

The table above highlights how UV exposure in Thornton 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.

Thornton'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
Thornton	3	4	7	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