Last updated: July 2, 2025
Understanding the UV Index is essential for residents of Yorktown, United States, as it plays a crucial role in protecting your skin from harmful ultraviolet rays. High UV levels can lead to sunburn, premature aging, and increase the risk of skin cancer, making it vital to be aware of daily fluctuations in UV exposure. Yorktown's Cfa climate results in varying UV intensity throughout the year, with peak levels reaching a significant 12 around midday, highlighting the importance of sun safety measures. Stay informed and enjoy the sun responsibly by checking the UV Index regularly!
As the sun rises, the UV Index starts at a mild 1 at 7:00 AM and remains low until 9:00 AM, where it climbs to 3. By 10:00 AM, the index accelerates to a moderate 5, but it’s at 11:00 AM that the heat intensifies, reaching 8. The peak occurs at 12:00 PM with a staggering value of 10, followed by the highest point of the day at 1:00 PM and 2:00 PM, where it maxes out at 12. After this peak, the index gradually declines: it drops to 10 by 3:00 PM and continues to decrease to 7 at 4:00 PM. By the late afternoon, the intensity wanes, falling to 5 at 5:00 PM and back down to 2 by 6:00 PM, before settling at 1 again as day turns to dusk by 7:00 PM. Remember to shield yourself during the midday hours when the UV radiation is at its most intense!
| 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 | 12 | extreme | 10 min |
| 14:00 | 12 | extreme | 10 min |
| 15:00 | 10 | very high | 15 min |
| 16:00 | 7 | high | 25 min |
| 17:00 | 5 | 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 |