Last updated: July 2, 2025
Understanding the UV Index is crucial for residents of Lancaster, United States, where sun exposure can significantly impact skin health and increase the risk of sunburn. As the sun climbs to its peak around midday, the UV levels in Lancaster often reach dangerous heights, making awareness of these levels essential for outdoor activities. With a Cfa climate, Lancaster experiences warm summers, and high UV Index readings—peaking at 11 around 1 PM—underscore the importance of adopting protective measures to safeguard your skin. Whether you’re enjoying a day in the park or working in your garden, knowing the UV Index can help you make informed choices to protect yourself from harmful effects.
As the sun rises, the UV Index begins its modest ascent, starting at a gentle 1 around 7:00 AM and 8:00 AM. By 9:00 AM, it picks up to 3, hinting at a sunnier day ahead. The peak intensity occurs from 11:00 AM to 1:00 PM, where it skyrockets to a striking 10 at 12:00 PM, reaching an impressive 11 by 1:00 PM—perfect for those sun-seeking adventurers! However, after this zenith, the UV Index gradually declines, dropping to 9 by 3:00 PM and further easing to a 4 by 5:00 PM. By 6:00 PM, it falls to 2, and as the sun sets, it returns to a safe 1 by 7:00 PM. Remember to take precautions during those peak hours to protect your skin from harmful rays!
| 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 | 10 | very high | 15 min |
| 15:00 | 9 | 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 values fluctuate significantly, indicating varying levels of sun exposure risk. January and December see moderate UV levels (Index 4), allowing for up to 30 minutes of safe sun exposure. As spring arrives, the risk increases sharply; February (Index 6) marks the beginning of high-risk months with a burn time of 25 minutes, escalating to very high levels in March and April (Index 8-10), where you should limit exposure to 15 minutes. The peak months for UV intensity occur in June and July, classified as extreme (Index 11), requiring careful sun protection measures within just 10 minutes. As summer fades, the UV Index remains high in August, then gradually decreases through September and October (Index 9-8, with 15 minutes burn time), before returning to high in November (Index 6, 25 minutes). Residents and visitors should prioritize sun protection, especially from March to August, ensuring to wear sunscreen, hats, and protective clothing during peak UV hours.
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 |
| Lancaster | 4 | 6 | 8 | 10 | 10 | 11 | 11 | 10 | 9 | 8 | 6 | 4 |
| Houston UVI | 5 | 8 | 9 | 11 | 11 | 12 | 12 | 11 | 10 | 9 | 7 | 5 |