UV Index in San Jose, United States

Last updated: June 2, 2025

Understanding the UV Index is essential for residents of San Jose, as it plays a critical role in safeguarding skin health and preventing sunburn. With the city’s Dfb climate offering plenty of sunny days, awareness of UV levels can help you make informed decisions about outdoor activities. As the UV Index reaches peak values of 12 and 13 around midday, the risk of overexposure rises significantly. By staying informed about UV levels, you can enjoy the California sunshine while protecting your skin from harmful effects.

Hourly UV Index in San Jose

Throughout the day, the UV Index experiences a dynamic shift, peaking at an impressive 13 between 1 PM and 2 PM, indicating a high risk of harm from unprotected sun exposure. The morning starts gently, with a UV Index of 1 at 7 AM, gradually rising to 4 by 9 AM. As the sun inches higher, the intensity increases sharply, reaching 10 by 11 AM and soaring to 12 by noon. Post-peak, the index begins to decline, dropping to 10 at 3 PM, before settling back to a mild 2 by 6 PM. This clear progression emphasizes the importance of sun protection during the midday hours when the UV Index is at its highest. Enjoy the sunshine, but remember to stay safe! ☀️

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	13	extreme	10 min
14:00	12	extreme	10 min
15:00	10	very high	15 min
16:00	7	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 San Jose

Throughout the year, UV Index levels exhibit significant seasonal changes, with high-risk months primarily falling between February and September. The index peaks in June and July at 13, categorized as extreme, indicating that unprotected skin can burn in as little as 10 minutes. March, April, and May also see very high to extreme levels, with UV indices of 10 to 12. Conversely, January, November, and December present lower risks with moderate to high levels, allowing for longer exposure times. Residents and visitors should take precautions during high-risk months by wearing sunscreen, protective clothing, and seeking shade, especially during peak sun hours to minimize the risk of skin damage.

Monthly Maximum UV Index for San Jose, United States

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

The table above highlights how UV exposure in San Jose 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.

San Jose'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
Houston UVI	5	8	9	11	11	12	12	11	10	9	7	5
San Jose	5	8	10	11	12	13	13	12	11	8	6	4