Last updated: May 3, 2025
Understanding the UV Index is essential for residents of San Jose, where the unique Csb climate brings a mix of warm, dry summers and mild winters. With peak UV levels soaring to 11 around midday, awareness of these figures is crucial for sunburn prevention and maintaining long-term skin health. By keeping an eye on the UV Index, you can better protect yourself and your loved ones from harmful sun exposure and enjoy the beautiful Californian sunshine safely. Whether you're out for a midday stroll or engaging in outdoor sports, knowing the UV risks can help you make informed choices and safeguard your skin.
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!
| 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 | 8 | very high | 15 min |
| 16:00 | 6 | high | 25 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, 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 |
| San Jose | 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 |