Last updated: May 3, 2025
In San Jose, United States, staying informed about the UV Index is crucial for safeguarding your skin from harmful sun exposure. Understanding UV levels not only helps in preventing painful sunburns but also plays a significant role in long-term skin health. With a BSk climate characterized by hot, dry summers, San Jose experiences periods of high UV exposure, especially during peak hours when indexes can soar to 12. By being aware of the UV Index, you can enjoy the beautiful Californian sunshine while protecting yourself from its potentially damaging effects.
The UV Index for the day reveals a dynamic shift in sun exposure, peaking dramatically between 11:00 AM and 1:00 PM. Starting the morning with a mild maximum of 2 at 7:00 AM, the index steadily rises, reaching 12 by midday—an indication of high risk for harm from unprotected sun exposure. As the afternoon progresses, it dips to 10 at 2:00 PM and then gradually decreases to a more moderate level of 4 by 4:00 PM. By the evening, the UV Index settles back down to 1 by 6:00 PM, signaling a safe time to enjoy the outdoors again. Be sure to protect your skin during those peak hours!
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 2 | low | 45 min |
| 08:00 | 3 | moderate | 30 min |
| 09:00 | 6 | high | 25 min |
| 10:00 | 9 | very high | 15 min |
| 11:00 | 11 | extreme | 10 min |
| 12:00 | 12 | extreme | 10 min |
| 13:00 | 12 | extreme | 10 min |
| 14:00 | 10 | very high | 15 min |
| 15:00 | 7 | high | 25 min |
| 16:00 | 4 | moderate | 30 min |
| 17:00 | 2 | low | 45 min |
| 18:00 | 1 | low | 45 min |
| 19:00 | 1 | low | 45 min |
Throughout the year, UV exposure varies significantly, with notable increases as we move from winter into summer. January begins with a moderate UV Index of 5, and while the risk starts low, it escalates quickly, peaking in the summer months. February sees a rise to a high UV Index of 7, and by March, it reaches 10, indicating a very high risk. The extreme category of UV Index 12 persists from May through August, marking these as the highest risk months for UV exposure, with a burn time as short as 10 minutes. As fall sets in, the UV Index decreases to 8 in October and 6 in November, with exposure categorizing back to very high and high, respectively. By December, the UV Index drops to 4, indicating a return to moderate exposure. Visitors and residents are advised to practice sun safety measures—including wearing sunscreen, protective clothing, and seeking shade, especially during the peak months of April to September when UV levels are most hazardous.
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 Jose | 5 | 7 | 10 | 11 | 12 | 12 | 12 | 12 | 11 | 8 | 6 | 4 |