Last updated: July 2, 2025
Understanding the UV Index is crucial for residents and visitors of South Yarmouth, United States, where the combination of a Cfa climate and seasonal sunshine presents varying UV exposure risks throughout the day. With UV levels peaking around noon—reaching as high as 9—awareness of sun intensity becomes essential for preventing sunburn and safeguarding skin health. By monitoring the UV Index, you can make informed decisions about outdoor activities and sun protection, ensuring that you enjoy South Yarmouth's beautiful beaches without compromising your well-being.
As the sun rises, the UV Index starts off relatively low, peaking at 1 at 7:00 AM. By 8:00 AM, it gently climbs to 2, but it’s not until 9:00 AM that the intensity begins to gather real momentum, reaching 4. The index rises sharply as the day progresses, hitting 6 by 10:00 AM, and then escalating to a striking 8 at 11:00 AM. The maximum intensity occurs at 12:00 PM and 1:00 PM, where it levels off at a high 9. This peak is maintained through 2:00 PM, after which the UV Index begins its descent, dropping to 7 at 3:00 PM, 5 at 4:00 PM, and further declining to 3 by 5:00 PM. By the evening, it gently falls back to 1 at both 6:00 PM and 7:00 PM, signaling a significant reduction in sun exposure. Overall, it's a day where protection from UV radiation is essential during peak hours!
| 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 | 9 | 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, UV exposure varies significantly, peaking during the late spring and summer months. From March to September, the UV Index escalates from 6 to a maximum of 10, indicating high to very high risk of harm from unprotected sun exposure. April through September are particularly critical months, with May, June, July, and August having an extremely high UV Index of 9 or 10, resulting in a burn time of just 15 minutes for fair-skinned individuals. Visitors and residents are strongly advised to take precautions during these high-risk months by wearing protective clothing, using broad-spectrum sunscreen, and seeking shade during peak sunlight hours. Conversely, November through February sees a decrease in UV levels, reaching a low of 2 in December, when exposure times can safely extend to 45 minutes.
UV Risk Categories
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| South Yarmouth | 3 | 4 | 6 | 8 | 9 | 10 | 9 | 9 | 8 | 6 | 4 | 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 |