Last updated: August 1, 2025
In Chantilly, United States, being aware of the UV Index is crucial for protecting your skin from harmful UV radiation. Understanding UV levels not only helps in preventing painful sunburns but also promotes long-term skin health, reducing the risk of skin cancer. With a Cfa climate characterized by warm summers, residents can experience elevated UV exposure, particularly during midday hours when the UV Index reaches its peak at 10. By staying informed about the UV Index, you can enjoy the beautiful sunny days of Chantilly while safeguarding your health with timely precautions.
The UV Index reveals a dynamic ascent and descent throughout the day, peaking with intensity during midday. Starting at a gentle 1 at 7:00 AM, it climbs steadily, reaching 10 by 1:00 PM and maintaining this highest level until 2:00 PM. This critical window indicates significant sun exposure, and it’s essential to take precautions. As the afternoon progresses, the index begins to taper off, dropping to 8 at 3:00 PM, then gradually falling to 1 by 7:00 PM. This data highlights the importance of being sun-smart during the peak hours to minimize UV exposure risks.
| 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 | 8 | very high | 15 min |
| 13:00 | 9 | very high | 15 min |
| 14:00 | 9 | very high | 15 min |
| 15:00 | 7 | high | 25 min |
| 16:00 | 5 | moderate | 30 min |
| 17:00 | 3 | moderate | 30 min |
| 18:00 | 2 | low | 45 min |
| 19:00 | 1 | low | 45 min |
Throughout the year, the UV Index demonstrates significant seasonal changes, highlighting the need for awareness regarding sun exposure. From January to February, UV levels are moderate (index 3-5), with a burn time of 30 minutes. As spring arrives in March, the index rises to 7, indicating high exposure risk with a reduced burn time of 25 minutes. The peak risk occurs from April through August, where the index reaches its highest levels (9-10) and burn times drop to just 15 minutes, categorizing these months as very high risk. In September and October, the UV index remains significant but decreases to high levels (7-8) with a burn time of 25 minutes. November and December return to moderate levels (index 3-5) with a burn time of 30 minutes. For visitors and residents alike, it is crucial to take protective measures, especially during the high-risk months from April to August, by using sunscreen, wearing protective clothing, and seeking shade during peak sunlight 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 |
| Chantilly | 3 | 5 | 7 | 9 | 10 | 10 | 10 | 9 | 8 | 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 |