UV Index in Fullerton, United States

Last updated: May 3, 2025

In Fullerton, United States, awareness of the UV Index is essential for ensuring your skin's health and preventing painful sunburns. With a Dfa climate, residents and visitors alike are exposed to varying UV levels throughout the day, peaking at a notable 10 between 1 PM and 2 PM. Understanding these UV levels is crucial, especially during sunny months, as they can significantly impact your skin health if not managed properly. By staying informed about the daily UV Index, you can make smarter decisions about sun protection and enjoy all that Fullerton has to offer while minimizing your risks.

Hourly UV Index in Fullerton

The UV Index throughout the day presents a clear narrative of rising intensity, peaking in the afternoon. Starting at 1 by 07:00, the UV levels gradually ascend, reaching 5 by 10:00. By 11:00, the index climbs to 7, and it soars to a striking 10 at 13:00—the optimal time for sun precautions. The intensity slightly wanes thereafter, dropping to 9 at 14:00 and continuing down to 4 by 17:00. As evening approaches, the UV Index dwindles to 1 by 19:00, signaling a return to safer levels. This data underscores the importance of sun safety measures during peak hours, particularly between 11:00 and 14:00.

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	1	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	10	very high	15 min
14:00	9	very high	15 min
15:00	8	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 Fullerton

Throughout the year, UV levels display significant variation, peaking during the summer months. The high-risk months for UV exposure are April through September, with UV Index values reaching their peak at 11 in June, indicating an extreme risk of harm from unprotected sun exposure. Visitors and residents are advised to take precautions during these months, including seeking shade, wearing protective clothing, and applying sunscreen regularly. During lower UV months, specifically January, February, November, and December, while risks are moderate, it's still wise to remain vigilant as UV rays can still cause harm. Being informed about UV Index levels can help ensure a safe and enjoyable outdoor experience year-round.

Monthly Maximum UV Index for Fullerton, United States

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

The table above highlights how UV exposure in Fullerton 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.

Fullerton'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
Fullerton	3	5	6	9	10	11	10	10	8	6	4	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