Last updated: July 2, 2025
Understanding the UV Index is crucial for residents and visitors of Boulder Creek, California. With its Csb climate, characterized by warm summers and cool winters, the region experiences varying levels of ultraviolet exposure, particularly during peak hours. Keeping a close eye on the UV Index not only helps in preventing sunburn but also plays a key role in maintaining long-term skin health. During the sunniest hours, like between 11 AM and 1 PM when the UV levels can soar to a high of 11, it’s essential to take precautions. By being informed and proactive, you can enjoy the beautiful outdoors of Boulder Creek while safeguarding your skin from harmful UV radiation.
As the day unfolds, the UV Index rises steadily, peaking at 11 around 1 PM—a clear signal for sun protection. Starting from a low of just 1 at 7 AM, it escalates through the morning, hitting 8 by 11 AM. At 12 PM, the intensity reaches a significant 10, before slightly diminishing to 9 at 3 PM and tapering off rapidly in the afternoon. As the sun begins to set, the UV levels drop to 4 by 5 PM, finally settling back to 1 by 7 PM. With this clear UV trajectory, staying cautious during the peak hours, especially from 11 AM to 2 PM, is essential for skin safety. Don your sunscreen and enjoy the sun responsibly!
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 1 | low | 45 min |
| 08:00 | 2 | low | 45 min |
| 09:00 | 4 | 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, 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 |
| Boulder Creek | 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 |