Last updated: June 2, 2025
In Jamestown, United States, being aware of the UV Index is crucial for maintaining skin health and preventing sunburn. Understanding the daily UV levels can help residents make informed choices about sun protection, especially during peak hours when indices soar to 11—a level that signifies an extreme risk of harm from unprotected sun exposure. Given Jamestown's Cfa climate—characterized by hot summers and ample sunshine—residents must stay vigilant about their UV exposure to safeguard their well-being during outdoor activities. Knowing when to seek shade or apply sunscreen can make all the difference in enjoying the sunny days responsibly.
Starting the day with a gentle UV Index of 1 at 7:00 AM, the sun quickly ramps up its intensity. By 8:00 AM, it reaches 3, but things really heat up as the clock strikes 9:00 AM with a 5. The peak sun hours are between 11:00 AM and 1:00 PM, where the UV Index soars to a significant 11, indicating a high risk of harm from unprotected sun exposure. After noon, the Index begins a gradual decline, dipping to 10 at 2:00 PM and then to 7 by 3:00 PM. As the afternoon wanes, the values drop further, settling back to 1 by 6:00 PM and 7:00 PM, providing a gentle close to the day's UV intensity. Remember to protect your skin during those peak hours!
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 1 | low | 45 min |
| 08:00 | 3 | moderate | 30 min |
| 09:00 | 5 | moderate | 30 min |
| 10:00 | 7 | high | 25 min |
| 11:00 | 9 | very high | 15 min |
| 12:00 | 11 | extreme | 10 min |
| 13:00 | 11 | extreme | 10 min |
| 14:00 | 10 | 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 experiences significant fluctuations, indicating varying levels of sun exposure risk. The high-risk months for UV exposure are primarily from April to August, where indices peak at 11 in June and July, categorized as extreme with a burn time of only 10 minutes. It is crucial for both visitors and residents to take precautions during this period, such as wearing protective clothing and applying sunscreen frequently. As spring transitions into summer, the UV index rises sharply, reaching very high levels in May and August, and dropping to high in March and October. The months of January, November, and December see lower risks with a moderate index of 3 or 5, allowing for more extended safe sun exposure times of 30 minutes. Visitors and residents should monitor UV levels closely and adjust outdoor activities accordingly to safeguard their skin health.
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 |
| Jamestown | 3 | 6 | 7 | 9 | 10 | 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 |