UV Index in Keystone, United States

Last updated: May 3, 2025

In Keystone, United States, understanding the UV Index is crucial for safeguarding your skin and overall health. With sunny, warm summers typical of the Dfa climate zone, local residents and visitors must be aware of UV levels to prevent sunburn and reduce long-term skin damage. The peak UV Index can reach a notable 9 during midday hours, indicating a high risk of harm from unprotected sun exposure. By staying informed about these levels, you can effectively enjoy the great outdoors while protecting your skin from harmful ultraviolet rays.

Hourly UV Index in Keystone

The UV Index for the day showcases a notable rise in intensity as the sun climbs higher in the sky. Starting at a low of 1 at 7:00 AM, the index gradually increases to a moderate level of 3 by 9:00 AM. However, from 10:00 AM onward, things heat up significantly, peaking at a scorching 9 from noon to 2:00 PM. As the afternoon progresses, the UV Index gradually dips back to a friendly 3 by 5:00 PM, then descends further to 1 by the time evening sets in. This pattern underscores the importance of sun protection during peak hours, especially between 11:00 AM and 2:00 PM, when UV levels are at their highest.

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	7	high	25 min
12:00	9	very high	15 min
13:00	9	very high	15 min
14:00	9	very high	15 min
15:00	7	high	25 min
16:00	5	moderate	30 min
17:00	3	moderate	30 min
18:00	2	low	45 min
19:00	1	low	45 min

Monthly UV Index Trends in Keystone

Throughout the year, the UV Index exhibits notable fluctuations, with high-risk months typically falling between April and September. During this period, the UV Index peaks in June at a severe level of 11, signifying an extreme exposure category with a burn time of just 10 minutes. Following closely are May and July, both rated as very high with indices of 9 and 10 respectively, while April and August maintain a very high category as well, with indices reaching 8. As winter approaches, the UV Index drops to a moderate level in January, February, November, and December, offering safer exposure times of up to 30 minutes. To protect yourself during peak UV times, especially from April to September, it's crucial to apply sunscreen regularly, wear protective clothing, and limit sun exposure during mid-day hours.

Monthly Maximum UV Index for Keystone, United States

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

The table above highlights how UV exposure in Keystone 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.

Keystone'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
Keystone	3	5	6	8	9	11	10	9	8	6	3	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