UV Index in Cupertino, United States

Last updated: May 3, 2025

Understanding the UV Index in Cupertino, California, is crucial for everyone who enjoys the outdoors in this vibrant city. With a climate classified as Csb, residents and visitors alike can expect significant UV exposure, especially during the peak hours from 10 AM to 4 PM. The UV levels can reach as high as 11, underscoring the importance of awareness to prevent sunburn and protect skin health. By staying informed about the UV Index, you can take proactive measures to enjoy the beautiful California sunshine while minimizing your risk of skin damage. Prioritize your health and safety by keeping an eye on those UV levels!

Hourly UV Index in Cupertino

As the sun rises, the UV Index begins at a mild 1 at 07:00, gradually escalating throughout the morning. By 10:00, it peaks at a robust 6, and then skyrockets to its maximum of 11 by 13:00—a time when protective measures become essential. The intensity starts to wane in the afternoon, dropping to 8 at 15:00, and further retreating to a gentle 1 by evening. It's a classic case of the sun's power, reminding us to stay vigilant and shield ourselves during those 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
09:003moderate30 min
10:006high25 min
11:008very high15 min
12:0010very high15 min
13:0011extreme10 min
14:0010very high15 min
15:008very high15 min
16:006high25 min
17:003moderate30 min
18:002low45 min
19:001low45 min

Monthly UV Index Trends in Cupertino

Throughout the year, UV exposure varies significantly, with the highest risk occurring during the late spring and summer months. March marks the start of increased UV intensity, reaching 8, categorizing it as very high, while April sees a further rise to 9. The peak UV index of 11, indicating an extreme exposure category, occurs from May to July, with the shortest burn time of just 10 minutes. As summer wanes, August and September still reflect high UV levels of 10 and 9, respectively. In contrast, January, November, and December are characterized by lower UV indices of 4, 5, and 3, which fall into the moderate category, allowing for longer safe exposure times of 30 minutes and 25 minutes in October. Visitors and residents are advised to take extra precautions, particularly from March through September when UV levels are at their most hazardous, including wearing sunscreen, protective clothing, and seeking shade during peak hours.

Monthly Maximum UV Index for Cupertino, United States

The monthly maximum UV Index (UVI) represents the highest UV radiation level recorded each month in Cupertino. It measures the strength of ultraviolet radiation from the sun and helps assess the risk of sunburn and UV-related health issues.
JanFebMarAprMayJunJulAugSepOctNovDec4589111111109753
Data source: Statistical UV Index data for Cupertino, 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 Cupertino UV Index with Other United States Cities

The table above highlights how UV exposure in Cupertino 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.
Cupertino'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
Cupertino4589111111109753
Los Angeles UVI46891011111010754
Houston UVI589111112121110975