Last updated: June 2, 2025
Understanding the UV Index is crucial for residents and visitors of Williamsburg, United States, where the warm Cfa climate often brings high sun exposure. Awareness of UV levels plays a vital role in preventing sunburn and protecting skin health, particularly during peak hours when readings reach as high as 10 between noon and 2 PM. With the sun's intensity varying throughout the day, being mindful of UV risks allows you to enjoy the lovely outdoor activities Williamsburg has to offer while keeping your skin safe.
The UV Index is a dynamic measure of solar intensity throughout the day, peaking dramatically at 12:00 PM with a notable 9, reaching its zenith at 1:00 PM and 2:00 PM with a maximum value of 10. During this period, it's essential to protect your skin from harmful UV rays. Early morning hours remain quite low, peaking at just 1 by 08:00 AM, while by 10:00 AM the index climbs to 5. As the sun continues to rise, it climbs swiftly to 7 by 11:00 AM, making midday the crucial time for sunscreen and shade. As the afternoon wanes, the UV Index gradually decreases, falling back to 5 by 5:00 PM, and finally settling at 1 by 7:00 PM, signaling a safe return to outdoor activities. Stay vigilant and enjoy the sunshine safely!
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 1 | low | 45 min |
| 08:00 | 1 | low | 45 min |
| 09:00 | 3 | moderate | 30 min |
| 10:00 | 5 | moderate | 30 min |
| 11:00 | 7 | high | 25 min |
| 12:00 | 9 | very high | 15 min |
| 13:00 | 10 | very high | 15 min |
| 14:00 | 10 | very high | 15 min |
| 15:00 | 9 | very high | 15 min |
| 16:00 | 7 | high | 25 min |
| 17:00 | 5 | moderate | 30 min |
| 18:00 | 3 | moderate | 30 min |
| 19:00 | 1 | low | 45 min |
Throughout the year, the UV Index exhibits notable seasonal changes, with the highest levels occurring from April to September. During this peak period, particularly in May, June, and July, the UV Index reaches 10—categorized as very high, necessitating vigilant sun protection measures. Visitors and residents should be particularly cautious in these months, as the burn time drops to just 15 minutes. March marks the transition to high exposure, with an index of 6, while October and November see a decline to moderate levels and longer burn times of 25 to 30 minutes. To safeguard against UV-related health risks, it is essential to wear sunscreen, hats, and protective clothing, especially during the high-risk months of April to September.
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 |
| Williamsburg | 3 | 5 | 6 | 9 | 10 | 10 | 10 | 9 | 8 | 6 | 4 | 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 |