UV Index in Walnut, United States

Last updated: June 2, 2025

Understanding the UV Index is crucial for residents of Walnut, California, where sunny days are common and the potential for skin damage is high. The UV Index provides valuable information on the sun's intensity, helping you to take proactive measures against sunburn and long-term skin health issues. With a Dfa climate, Walnut experiences significant UV exposure, especially during peak hours between 10 AM and 2 PM, when levels can soar to a dangerous 10. Staying informed about UV levels is essential for enjoying the outdoors safely while protecting your skin from harm.

Hourly UV Index in Walnut

The UV Index today paints a picture of intensity as the sun reaches its zenith. Starting off mild at 1 at 07:00, the index quickly climbs to 4 by 09:00, signaling the onset of stronger rays. The sun's power peaks dramatically, with a scorching 10 recorded between 12:00 and 14:00, making this the most critical time for sun protection. As the afternoon wanes, the UV Index dips to 8 at 15:00, then gradually declines to 3 by 17:00, before returning to a gentle 1 by 19:00. It's a day that underscores the importance of safeguarding your skin during those midday hours!

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	9	very high	15 min
12:00	10	very high	15 min
13:00	10	very high	15 min
14:00	10	very high	15 min
15:00	8	very high	15 min
16:00	6	high	25 min
17:00	3	moderate	30 min
18:00	2	low	45 min
19:00	1	low	45 min

Monthly UV Index Trends in Walnut

Throughout the year, the UV Index experiences notable fluctuations, with the highest risk months occurring from March to September, when the index consistently ranges between 6 and 10. Specifically, April to August feature very high levels, with peak values reaching 10 in June and July, corresponding to a dangerously short burn time of 15 minutes. In contrast, January and December present lower UV risks, categorized as moderate to low, with corresponding burn times of 30 minutes and 45 minutes, respectively. To safeguard your skin, it is crucial for visitors and residents to adopt protective measures, especially during the peak months by using sunscreen, wearing protective clothing, and seeking shade during midday hours to reduce UV exposure effectively.

Monthly Maximum UV Index for Walnut, United States

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

The table above highlights how UV exposure in Walnut 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.

Walnut'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
Walnut	3	5	6	8	9	10	10	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