Last updated: July 2, 2025
In Mountain View, United States, staying informed about the UV Index is crucial for protecting your skin and overall health. The UV index measures the strength of ultraviolet radiation from the sun, which peaks in the late morning and early afternoon. Understanding these levels is vital to prevent sunburn and long-term skin damage, especially given Mountain View's sunny Cfa climate, which often brings high UV exposure from late spring to early fall. With peak UV Index values soaring to 11 during midday hours, being proactive about sun safety can make all the difference in enjoying the beautiful California weather while safeguarding your skin.
The UV Index for today shows a dramatic rise as the sun ascends into the sky. Starting at a mild 1 by 07:00, the index gradually builds, reaching 3 by 09:00 and peaking at an intense 11 at 13:00—a level where sun protection is crucial. From this pinnacle, the values start to decline, tapering off to 10 at 14:00 and then gradually decreasing through the afternoon and evening, with values of 6 at 16:00 and sliding down to 1 by 19:00. Plan your outdoor activities accordingly, and remember to protect your skin during those peak hours!
| 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 | 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, the UV Index exhibits significant seasonal changes, with the highest levels occurring in May, June, and July, where it reaches an extreme index of 11. These months pose the greatest risk for sunburn, with a quick burn time of just 10 minutes. The high-risk months to be particularly cautious are March through August, as the UV Index remains very high to extreme during this period. Visitors and residents should take proactive measures, including wearing protective clothing, applying broad-spectrum sunscreen, and seeking shade during peak sunlight hours, especially from 10 a.m. to 4 p.m. Conversely, in the winter months of December and January, the UV Index is lower at 3-4, indicating a moderate risk with a burn time of 30 minutes, allowing for slightly more leeway in sun exposure. Regardless of the season, it is essential to stay informed and protect yourself from harmful UV rays.
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 |
| Los Angeles UVI | 4 | 6 | 8 | 9 | 10 | 11 | 11 | 10 | 10 | 7 | 5 | 4 |
| Mountain View | 4 | 6 | 8 | 10 | 11 | 11 | 11 | 10 | 9 | 7 | 5 | 3 |
| Houston UVI | 5 | 8 | 9 | 11 | 11 | 12 | 12 | 11 | 10 | 9 | 7 | 5 |