Last updated: May 3, 2025
Understanding the UV Index is essential for residents of Yorktown, United States, where the humid subtropical climate (Cfa) brings long, sunny days that can lead to significant UV exposure. Knowing the daily UV levels not only helps you enjoy outdoor activities safely but also plays a crucial role in preventing sunburn and protecting your overall skin health. With peak UV Index values soaring to 11 between noon and 2 PM, it’s vital to remain vigilant and take precautions during those hours to reduce the risk of harmful effects. Stay informed and enjoy the sunshine safely in Yorktown!
The UV Index for the day showcases a dramatic increase in intensity as the sun climbs higher in the sky. Starting at a mild 1 at 07:00, it remains low throughout the morning, only reaching 3 by 09:00. However, by 11:00, the index skyrockets to 8, peaking at an intense 11 from 13:00 to 14:00. As the afternoon wanes, the UV levels gradually decrease, dropping to 4 by 17:00 and tapering off to 1 once again by 19:00. It's clear that midday hours pose the greatest risk for sun exposure, making it crucial to take precautions during the peak hours from 11:00 to 14:00.
| 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 | 8 | very high | 15 min |
| 12:00 | 10 | very high | 15 min |
| 13:00 | 11 | extreme | 10 min |
| 14:00 | 11 | extreme | 10 min |
| 15:00 | 10 | very high | 15 min |
| 16:00 | 7 | high | 25 min |
| 17:00 | 4 | moderate | 30 min |
| 18:00 | 2 | low | 45 min |
| 19:00 | 1 | low | 45 min |
Throughout the year, UV Index levels fluctuate significantly, with the high-risk months spanning from February to September. During this period, the UV Index reaches extremes, peaking at 12 in June and July, signaling a very high to extreme risk of harm from unprotected sun exposure. Notably, April, May, June, July, August, and September all maintain an index of 11 or higher, presenting a burn time of only 10 minutes. As such, it is crucial for visitors and residents to take precautions, such as wearing sunscreen, protective clothing, and seeking shade during peak sunlight hours, particularly from late morning to early afternoon. In contrast, late fall and winter months like November and December exhibit moderate UV levels, allowing for a more extended safe exposure time of 25-30 minutes. However, vigilance remains urged year-round to safeguard against UV damage.
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 |
| 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 |
| Yorktown | 5 | 8 | 9 | 11 | 11 | 12 | 12 | 11 | 11 | 9 | 7 | 5 |