Last updated: August 1, 2025
Understanding the UV Index is crucial for residents of Princeton, United States, as it directly impacts sun safety and skin health. With UV levels peaking at 10 around midday, awareness can help prevent sunburn and long-term skin damage, ensuring you enjoy the sun responsibly. Princeton's Dfb climate means you experience varied weather, but during the warmer months, the risks of UV exposure increase significantly. Stay informed about the UV Index to protect yourself and your loved ones from harmful sun rays while making the most of your outdoor activities!
As the sun rises, the UV Index starts its ascent, with a gentle 1 at 07:00. By 08:00, it begins to climb, reaching 2, signaling a reminder to take care. The real intensity kicks in at 10:00, where the index peaks at 6, escalating to a scorching 9 by noon. The hottest moment arrives at 13:00, showcasing a dramatic 10—a level that demands serious sun protection. Although the UV level begins to drop after this peak, it remains notable; at 14:00, it settles at 9, then declines gently, hitting 3 by 17:00. As daylight fades towards the evening, it tapers off to 2 at 18:00 and finally returns to a safe 1 by 19:00. It's a vivid reminder of the sun's power throughout the day!
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 1 | low | 45 min |
| 08:00 | 2 | 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 | 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 | 1 | low | 45 min |
| 19:00 | 1 | low | 45 min |
Throughout the year, UV levels fluctuate significantly, with high-risk months generally spanning from April to August. During this period, particularly in May and June, the UV Index peaks at 10, indicating a very high risk of harm from unprotected sun exposure, with a rapid burn time of just 15 minutes. Comparatively, the UV Index is moderate in the winter months of January to March, and again in October and November, where the burn time extends to 30 minutes. As the year progresses into December, the UV risk decreases further, classified as low, allowing for a safer 45-minute exposure before burning. Visitors and residents are advised to be vigilant in the spring and summer months, taking necessary precautions such as applying sunscreen, wearing protective clothing, and seeking shade during the peak sun hours to minimize the risks of skin damage.
UV Risk Categories
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Princeton | 3 | 4 | 5 | 8 | 9 | 10 | 10 | 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 |