UV Index in Alta Sierra, United States

Last updated: July 2, 2025

In Alta Sierra, United States, being aware of the UV Index is vital for protecting your skin and overall health. Understanding UV levels not only aids in preventing painful sunburns but also plays an essential role in minimizing long-term skin damage and the risk of skin cancer. Nestled in a high desert climate (BSk), Alta Sierra experiences elevated UV exposure, particularly from late morning to early afternoon, where indexes can soar as high as 12. Being informed about daily UV conditions empowers residents and visitors to take proactive measures against harmful rays, ensuring a safe and enjoyable time outdoors.

Hourly UV Index in Alta Sierra

At sunrise, the UV Index begins its steady climb, starting at a safe 1 at 07:00. As the morning progresses, it escalates to 2 by 08:00 and reaches a pleasant 4 by 09:00. However, the real intensity hits between 10:00 and 13:00, with the UV Index peaking at a scorching 12 at 12:00, indicating a high risk of harm from unprotected sun exposure. As the afternoon unfolds, levels gradually descend, hitting 9 at 15:00 before tapering off to 4 by 17:00. By the evening hours, the index returns to a mild 1 by 19:00, reminding us of the importance of sunscreen amidst the sun's powerful midday rays.

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	7	high	25 min
11:00	10	very high	15 min
12:00	12	extreme	10 min
13:00	12	extreme	10 min
14:00	11	extreme	10 min
15:00	9	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 Alta Sierra

As we observe seasonal changes in the UV Index, it becomes clear that higher levels of ultraviolet radiation occur during the warmer months. The high-risk months peak from March to August, with May and June reaching extreme levels (UV Index 11-12) and burn times as low as 10 minutes. Visitors and residents are strongly advised to take precautions during these months by seeking shade, wearing protective clothing, and using sunscreen, especially between 10 AM and 4 PM when UV exposure is at its highest. January, November, and December are comparatively safer, with moderate UV levels (Index 4-5) and longer burn times of 30 minutes. Staying informed about the UV Index is essential for maintaining skin health year-round.

Monthly Maximum UV Index for Alta Sierra, United States

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

The table above highlights how UV exposure in Alta Sierra 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.

Alta Sierra'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
Los Angeles UVI	4	6	8	9	10	11	11	10	10	7	5	4
Alta Sierra	4	6	9	10	11	12	12	11	10	8	5	4
Houston UVI	5	8	9	11	11	12	12	11	10	9	7	5