Last updated: May 3, 2025
Understanding the UV Index in Hyannis is crucial for protecting your skin against harmful ultraviolet radiation. With summer temperatures in this Cfa climate zone often soaring, UV levels can reach concerning heights, especially between 11 AM and 2 PM when the index hits a peak of 9. Being aware of these UV levels is essential for sunburn prevention and maintaining long-term skin health, as even short exposure can lead to irreversible damage. Stay informed and take necessary precautions to enjoy the beautiful sunny days in Hyannis without jeopardizing your well-being!
The UV Index for the day reveals an intensifying sun, peaking between 12:00 PM and 1:00 PM with a striking value of 9. Early in the day, at 7:00 AM, the index starts low at 1, allowing a gradual increase to 2 by 8:00 AM. As the hours progress, the UV exposure rises sharply, hitting 6 by 10:00 AM, and climbing to its maximum of 8 at 11:00 AM before reaching its zenith. After this midday spike, a gentle decline begins; the levels drop back to 8 at 2:00 PM, then 6 at 3:00 PM, and further decrease to 2 by 5:00 PM. The sun sets on the day’s UV journey with lingering low values of 1 for the last few hours. It's a reminder to stay protected during those 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 | 8 | very high | 15 min |
| 15:00 | 6 | 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, 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 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Hyannis | 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 |