Last updated: May 3, 2025
Awareness of the UV Index is crucial for residents and visitors in Phoenix, United States, where the sun shines brightly and UV exposure can be intense. Understanding UV levels is essential for preventing sunburn and protecting your long-term skin health—especially in a city known for its arid climate and high temperatures. During peak hours, particularly between 10 AM and 3 PM, the UV Index can reach as high as 9, indicating a significant risk of harm from unprotected sun exposure. With this valuable information, you can enjoy the outdoors safely while minimizing your risk of sun-related damage.
Experience the dynamic ebb and flow of the UV Index throughout the day! Starting gently at 1 by 7:00 AM, the index gradually climbs as the sun rises, reaching a comfortable 2 by 8:00 AM. As mid-morning approaches, the intensity spikes, peaking at an impressive 9 between 12:00 PM and 2:00 PM, when sun protection is essential. The afternoon sees a slight dip, with readings falling to 7 at 3:00 PM and 5 by 4:00 PM. As the sun begins to set, the index declines gracefully back to 1 by 7:00 PM. Be sure to soak in the sunshine wisely and stay safe during those peak UV hours!
| 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 | 6 | high | 25 min |
| 11:00 | 7 | high | 25 min |
| 12:00 | 9 | 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 |
As the seasons change, the UV Index reveals significant fluctuations in sun exposure risk. Winter months (January and February) have moderate UV levels with an index of 3 to 4, leading to a burn time of approximately 30 minutes. Transitioning into spring, the UV Index rises sharply: March reaches a high of 6, and by April it soars to 8, signaling the start of very high risk months with a burn time reduced to 15 minutes. The summer months (May through August) maintain this high threat level, peaking at 10 in June, necessitating extra precautions for outdoor activities. As September and October approach, the UV Index decreases to 7 and 6, respectively, still indicating a high risk for 25 minutes of safe sun exposure. November and December see a return to moderate and low levels for UV exposure, with longer burn times of 30 to 45 minutes. Residents and visitors are advised to take protective measures, especially from April to August, including wearing sunscreen, protective clothing, and limiting time in direct sunlight during peak hours.
UV Risk Categories
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Phoenix | 3 | 4 | 6 | 8 | 9 | 10 | 9 | 9 | 7 | 6 | 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 |