Last updated: May 3, 2025
Understanding the UV Index is crucial for residents and visitors of Cambridge, United States, where the climate can expose individuals to significant UV radiation, especially during the peak summer months. By monitoring UV levels, you can take proactive steps to prevent sunburn and protect your skin health. In Cambridge's Dfb climate zone, UV exposure can peak sharply around midday, reaching levels as high as 9, underscoring the necessity of sun safety measures. Awareness of daily fluctuations in the UV Index enables you to enjoy the outdoors while minimizing the risk of harmful effects from the sun’s rays.
The UV Index reveals a dynamic pattern throughout the day, starting at a mild 1 at 07:00 and steadily rising as the sun reaches its peak. By 10:00, it escalates to a moderate 6, reaching 8 at 11:00 and peaking at an intense 9 from 12:00 to 13:00. This period signifies the greatest caution for sun exposure, making it essential to seek shade and wear protective clothing. As the afternoon unfolds, the index begins to dip, dropping to 8 at 14:00, then declining further to 7 by 15:00, and tapering down to 1 by 19:00. Overall, it’s a day that encourages sun safety awareness, particularly during the midday hours when UV radiation is at its strongest.
| 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 | 9 | very high | 15 min |
| 13:00 | 9 | very high | 15 min |
| 14:00 | 8 | very high | 15 min |
| 15:00 | 7 | high | 25 min |
| 16:00 | 5 | moderate | 30 min |
| 17:00 | 3 | moderate | 30 min |
| 18:00 | 1 | low | 45 min |
| 19:00 | 1 | low | 45 min |
Throughout the year, the UV Index exhibits significant seasonal variation, with the highest levels occurring in late spring and summer months. Notably, April to August are identified as high-risk months, where the UV Index peaks at 10 in June and remains at 9 in both July and August, indicating very high exposure and requiring a burn time of only 15 minutes. In contrast, the winter months of January, February, and December show lower UV levels, with a moderate index of 3 and 2 respectively, allowing for longer exposure times without severe risk of burns. Visitors and residents are advised to adopt protective measures during high-risk months, such as applying sunscreen, wearing protective clothing, and seeking shade, to minimize the risk of overexposure.
UV Risk Categories
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Cambridge | 3 | 4 | 6 | 8 | 9 | 10 | 9 | 9 | 7 | 5 | 3 | 2 |
| 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 |