Last updated: May 3, 2025
Understanding the UV Index is crucial for residents of Palo Alto, where sunny days are plentiful in the Dfa climate zone. By staying informed about UV levels, you can take proactive measures to prevent sunburn and protect your skin health. With peak UV Index values reaching as high as 10 between 12 PM and 1 PM, knowing when to seek shade or apply sunscreen can make all the difference in safeguarding yourself from potential damage. As you enjoy the local outdoor activities, stay vigilant about the risks associated with UV exposure to ensure a safe and healthy experience under the Californian sun.
The UV Index throughout the day showcased a significant rise, peaking at 10 between 1 PM and 2 PM, indicating the most intense sun exposure. Early morning hours began with a mild UV Index of 1 at 7 AM, gradually climbing to 3 by 9 AM. As the sun climbed higher, it reached 8 at 11 AM, surging to 9 at noon. Following the peak, there was a slight decline, with values dropping to 8 at 3 PM and gradually easing to 1 by 7 PM. For those spending time outdoors, the window between 11 AM and 3 PM necessitated cautious sun protection strategies, while the morning and evening hours offered a more manageable UV exposure.
Time | UVI | Category | Time to Burn |
---|---|---|---|
07:00 | 1 | low | 45 min |
08:00 | 2 | low | 45 min |
09:00 | 3 | moderate | 30 min |
10:00 | 6 | high | 25 min |
11:00 | 8 | very high | 15 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 | 5 | moderate | 30 min |
17:00 | 3 | moderate | 30 min |
18:00 | 2 | low | 45 min |
19:00 | 1 | low | 45 min |
Throughout the year, UV exposure varies significantly, peaking during late spring and summer months. High-risk months for UV exposure are April through September, where the UV Index frequently reaches levels classified as very high; particularly notable are May, June, and July, when it consistently hits a maximum of 10. Visitors and residents are advised to take precautions during these months, with burn times dramatically reduced to as little as 15 minutes. In contrast, January, February, and November present moderate UV levels, and December has a low index, making sun safety measures less critical during these months. To protect against skin damage, it is essential to wear sunscreen, seek shade, and wear protective clothing, especially between peak months of April and September.
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 |
Palo Alto | 3 | 5 | 6 | 9 | 10 | 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 |