UV Index in Challis, United States

Last updated: June 2, 2025

Understanding the UV Index is crucial for residents and visitors in Challis, United States, as it helps gauge the strength of ultraviolet radiation from the sun. With peak UV levels reaching up to 11 during the sunniest hours, being aware of these readings is essential for sunburn prevention and maintaining skin health. Challis, situated in a Dfb climate zone, experiences varying UV exposure risks throughout the day, especially during the summer months. By staying informed about the UV Index, you can protect yourself and your loved ones from the harmful effects of UV rays, ensuring a safer outdoor experience.

Hourly UV Index in Challis

The UV Index shows a dramatic rise in the morning, starting at 1 at 7:00 AM and reaching a moderate 3 by 9:00 AM. As the day progresses, the intensity peaks at a striking 11 between 1:00 PM and 2:00 PM, indicating a high risk of harm from unprotected sun exposure. Those venturing outdoors during peak hours should consider protective measures, as the index begins to decline after 2:00 PM, dropping to 10 at 3:00 PM, before tapering off to 3 by 6:00 PM. This UV Index pattern highlights the importance of staying sun-safe during the height of the afternoon.

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	3	moderate	30 min
10:00	5	moderate	30 min
11:00	8	very high	15 min
12:00	10	very high	15 min
13:00	11	extreme	10 min
14:00	11	extreme	10 min
15:00	10	very high	15 min
16:00	8	very high	15 min
17:00	5	moderate	30 min
18:00	3	moderate	30 min
19:00	2	low	45 min

Monthly UV Index Trends in Challis

Throughout the year, UV exposure varies significantly, with the highest risk months typically from March to August. During this period, the UV Index peaks at 11, indicating an extreme exposure category in May, June, and July, where a burn can occur in as little as 10 minutes. Visitors and residents should take extra precautions during these months, such as seeking shade, wearing protective clothing, and applying sunscreen regularly. As summer transitions into fall, UV levels gradually decrease, but September still presents a very high risk with an index of 9. Conversely, winter months, especially December and January, exhibit much lower UV indices, ranging from 2 to 3, which means prolonged exposure is less of a concern. Overall, being UV-aware and practicing sun safety is crucial during the high-risk months.

Monthly Maximum UV Index for Challis, United States

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

The table above highlights how UV exposure in Challis 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.

Challis'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
Challis	3	5	8	9	11	11	11	10	9	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