UV Index in California, United States

Last updated: June 2, 2025

In sunny California, awareness of the UV Index is crucial for protecting your skin and overall health under the bright skies of this Cfa climate zone. Understanding the daily variations in UV levels can help you prevent sunburn and long-term skin damage, particularly during peak hours when the index reaches an alarming 10 at noon and 1 PM. With California's diverse landscapes and outdoor lifestyle, being informed about UV risks is essential for everyone, ensuring you can enjoy the sun safely while safeguarding your skin health. Remember, knowledge is your best defense against harmful UV rays!

Hourly UV Index in California

The UV index on this particular day presents a notable trend as the sun rises and peaks. Starting at 07:00, the index is a gentle 1, gradually climbing to 2 by 08:00. The ascent continues as it reaches 4 at 09:00 and hits 6 by 10:00. Midday shines brightest, with the index soaring to a maximum of 10 at both 12:00 and 13:00, indicating a high potential for skin damage without protection. As the day progresses, values begin to dip, falling to 9 at 14:00, and then decreasing further to 8 at 15:00. By 16:00, the UV index drops to 6, and as evening approaches, it relaxes to 3 at 17:00, down to 2 by 18:00, and finally retreating to 1 at 19:00. It's a day that emphasizes the importance of sun protection during the peak 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.
TimeUVICategoryTime to Burn
07:001low45 min
08:002low45 min
09:004moderate30 min
10:006high25 min
11:008very high15 min
12:0010very high15 min
13:0010very high15 min
14:009very high15 min
15:008very high15 min
16:006high25 min
17:003moderate30 min
18:002low45 min
19:001low45 min

Monthly UV Index Trends in California

Throughout the year, UV exposure varies significantly, with the high-risk months spanning from April to September. During this period, the UV Index reaches very high levels, peaking at 10 in May, June, July, and August, where the burn time is as short as 15 minutes. In contrast, January, February, November, and December present moderate risk with an Index of 3 to 5, allowing up to 30 minutes of safe sun exposure. Residents and visitors should take precautions during the spring and summer months, including wearing protective clothing, using sunscreen with high SPF, and seeking shade during peak hours to minimize the risk of sunburn and long-term skin damage. Remember, even on cloudy days, UV rays can still penetrate, so remain vigilant year-round.

Monthly Maximum UV Index for California, United States

The monthly maximum UV Index (UVI) represents the highest UV radiation level recorded each month in California. It measures the strength of ultraviolet radiation from the sun and helps assess the risk of sunburn and UV-related health issues.
JanFebMarAprMayJunJulAugSepOctNovDec3579101010108753
Data source: Statistical UV Index data for California, 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 California UV Index with Other United States Cities

The table above highlights how UV exposure in California 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.
California's solar exposure compared to other cities in United States. Generated using Copernicus Atmosphere Monitoring Service information.
 JanFebMarAprMayJunJulAugSepOctNovDec
Chicago UVI34689101098642
Brooklyn UVI35681010998642
New York City UVI35681010998642
California3579101010108753
Los Angeles UVI46891011111010754
Houston UVI589111112121110975