Last updated: July 2, 2025
In Hopkinton, United States, being aware of the UV Index is crucial for safeguarding your skin against harmful ultraviolet radiation. Understanding UV levels not only helps in preventing painful sunburns but also plays a significant role in maintaining long-term skin health. With a Cfb climate, Hopkinton experiences variable sunshine, leading to moments of high UV exposure, especially between late morning and early afternoon when the UV Index peaks at 9. By staying informed about UV levels, residents can better protect themselves from the hidden risks of sun exposure.
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 |
As the seasons change, the UV Index exhibits significant fluctuations, indicating varying levels of sun exposure risk. From January to March, the UV Index starts off in the moderate range (3-6), suggesting a burn time of 30 minutes in January and February, but decreases to 25 minutes in March. The high-risk months emerge from April to September, where the Index rises dramatically to the very high range (8-10), with a critical burn time dropping as low as 15 minutes in April, May, June, July, August, and September. October sees a decline back to a high UV Index (6), allowing for 25 minutes of exposure before burning, while November and December move back into moderate and low categories (4 and 2, respectively) with more forgiving burn times of 30 minutes and 45 minutes. Visitors and residents are strongly advised to take precautions during the high-risk months by wearing sunscreen, protective clothing, and seeking shade, particularly when the UV Index is at its peak in the summer months.
UV Risk Categories
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Hopkinton | 3 | 5 | 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 |