Last updated: May 3, 2025
In Philadelphia, being aware of the UV Index is crucial for protecting your skin and overall health. Understanding the levels of ultraviolet radiation can help you take proactive measures against sunburn and long-term skin damage. With a Dfb climate, Philadelphia experiences varying UV exposure throughout the year, peaking during summer months when midday readings can soar to 9—a significant risk for unprotected skin. By staying informed about the UV Index, you can enjoy the outdoors safely while minimizing the potential harms of excessive sun exposure.
The UV Index today presents a notable climb as the sun ascends, peaking at 9 around noon and early afternoon, signaling very high sun exposure risk. Starting gently at 1 by 7 AM, the index rises steadily, reaching 6 by 10 AM and then surging to its maximum of 9 between 12 PM and 1 PM. Early afternoon brings a slight decline to 8 at 2 PM, followed by a gradual decrease through the later hours, settling back to 1 by 7 PM. With this trajectory, it's crucial to take precautions during the peak hours of 11 AM to 1 PM, ensuring skin protection against harmful UV rays. Stay safe and enjoy the sun wisely!
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 1 | low | 45 min |
| 08:00 | 2 | low | 45 min |
| 09:00 | 4 | moderate | 30 min |
| 10:00 | 6 | high | 25 min |
| 11:00 | 8 | very high | 15 min |
| 12:00 | 9 | very high | 15 min |
| 13:00 | 9 | very high | 15 min |
| 14:00 | 8 | 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, UV exposure varies significantly, with the highest risk months occurring from April to August, where the UV Index consistently reaches 9, classifying it as very high. During these months, the burn time is a mere 15 minutes, emphasizing the need for caution. As winter approaches, the UV Index decreases, dropping to 2 in January and December, indicating a low risk of UV exposure, while February and March see moderate levels with indices of 4 and 5, respectively. Visitors and residents should prioritize protective measures such as using sunscreen, wearing protective clothing, and seeking shade, especially in the spring and summer months, when the sun's intensity is at its peak. Staying informed and alert can help mitigate the risks associated with UV exposure year-round.
UV Risk Categories
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Philadelphia | 2 | 4 | 5 | 8 | 9 | 9 | 9 | 9 | 7 | 5 | 3 | 2 |
| 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 |