Last updated: July 2, 2025
Understanding the UV Index in Cupertino, United States, is essential for protecting your skin from harmful ultraviolet rays. With its Mediterranean climate, Cupertino experiences significant sun exposure, especially during the peak hours of 11 AM to 3 PM when UV levels can reach as high as 11. Being aware of UV levels is crucial for sunburn prevention and maintaining overall skin health. By monitoring the UV Index, residents can make informed decisions about outdoor activities, ensuring they stay safe while enjoying the beautiful California sunshine.
As the day unfolds, the UV Index rises steadily, peaking at 11 around 1 PM—a clear signal for sun protection. Starting from a low of just 1 at 7 AM, it escalates through the morning, hitting 8 by 11 AM. At 12 PM, the intensity reaches a significant 10, before slightly diminishing to 9 at 3 PM and tapering off rapidly in the afternoon. As the sun begins to set, the UV levels drop to 4 by 5 PM, finally settling back to 1 by 7 PM. With this clear UV trajectory, staying cautious during the peak hours, especially from 11 AM to 2 PM, is essential for skin safety. Don your sunscreen and enjoy the sun responsibly!
| 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 | 8 | very high | 15 min |
| 12:00 | 10 | very high | 15 min |
| 13:00 | 11 | extreme | 10 min |
| 14:00 | 10 | very high | 15 min |
| 15:00 | 9 | 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 |
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.
UV Risk Categories
| 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 |
| Cupertino | 4 | 5 | 8 | 9 | 11 | 11 | 11 | 10 | 9 | 7 | 5 | 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 |