Last updated: July 2, 2025
Understanding the UV Index is crucial for residents of San Carlos, United States, where the sunny climate can lead to high levels of ultraviolet radiation. Being aware of UV levels helps in preventing sunburn and maintaining long-term skin health, safeguarding against risks associated with excessive sun exposure. With a hot-summer humid continental climate, typical UV exposure in San Carlos peaks significantly between late morning and early afternoon, reaching a maximum index of 12—indicating a very high risk of harm from unprotected sun exposure. Stay informed and protected to enjoy the beautiful weather safely!
As the sun rises, the UV Index slowly climbs, starting at a low 1 at 07:00 and 08:00. By 09:00, it slightly increases to 2. However, the real intensity kicks in as the day progresses, peaking at an impressive 12 between 13:00 and 14:00. This is the critical time when sun protection is essential, given the dangerous exposure level. As the afternoon wanes, the index starts to decrease, dropping to 10 by 15:00 and further declining to 5 at 17:00. Finally, as the sun sets, it returns to a mild 1 by 19:00. Take note of these fluctuations, as they are crucial for staying safe under the sun!
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 1 | low | 45 min |
| 08:00 | 1 | low | 45 min |
| 09:00 | 2 | low | 45 min |
| 10:00 | 5 | moderate | 30 min |
| 11:00 | 8 | very high | 15 min |
| 12:00 | 10 | very high | 15 min |
| 13:00 | 12 | extreme | 10 min |
| 14:00 | 12 | extreme | 10 min |
| 15:00 | 10 | very high | 15 min |
| 16:00 | 8 | very high | 15 min |
| 17:00 | 5 | moderate | 30 min |
| 18:00 | 2 | low | 45 min |
| 19:00 | 1 | low | 45 min |
Throughout the year, the UV Index fluctuates significantly, with high-risk months typically falling between February and September. During this time, values soar to extreme levels of 12, especially in May through August, where the recommended burn time is only 10 minutes. In March and April, the index remains in the very high to extreme categories, with burn times decreasing to just 10-15 minutes. As summer gradually transitions into fall, the UV Index begins to decline, allowing for slightly longer burn times in October at 15 minutes, but still indicating a very high risk. For winter months, January, November, and December maintain a high exposure category but extend burn times back to 25 minutes. Visitors and residents should remain vigilant, particularly during the peak UV months, taking proactive measures such as wearing sunscreen, protective clothing, and seeking shade during peak hours to mitigate the risks associated with intense sun exposure.
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 |
| Houston UVI | 5 | 8 | 9 | 11 | 11 | 12 | 12 | 11 | 10 | 9 | 7 | 5 |
| San Carlos | 6 | 9 | 10 | 11 | 12 | 12 | 12 | 12 | 11 | 9 | 7 | 6 |