Last updated: June 2, 2025
In Riley, United States, understanding the UV Index is essential for protecting your skin and overall health. With high UV levels peaking during midday, it's crucial to stay informed about sun exposure, as even short periods can lead to painful sunburns and long-term skin damage. Riley's Cfa climate, characterized by hot summers, intensifies the risk of harmful UV rays, making it vital to check the UV Index regularly. By being aware of daily fluctuations, you can take the necessary precautions to enjoy the outdoors safely and maintain healthy skin.
The UV Index throughout the day reveals a fascinating journey of sun exposure. Starting at a gentle level of 1 at 07:00 and 08:00, the index begins to rise steadily, hitting 3 by 09:00. As the sun reaches its peak, the intensity escalates dramatically, soaring to 10 at noon and peaking at 11 from 13:00 to 14:00—ideal for sun protection measures! The afternoon sees a gradual decline, with values dropping to 9 at 15:00, then further diminishing to 2 by 18:00, and finally settling back at 1 by 19:00. Whether lounging in the sun or engaging in outdoor activities, awareness of this UV landscape is essential for safe enjoyment!
| 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 | 11 | extreme | 10 min |
| 15:00 | 9 | very high | 15 min |
| 16:00 | 7 | high | 25 min |
| 17:00 | 5 | moderate | 30 min |
| 18:00 | 2 | low | 45 min |
| 19:00 | 1 | low | 45 min |
Throughout the year, seasonal UV changes reflect a pattern of increasing intensity from winter to summer and a decline toward winter again. High-risk months occur from March to August, peaking in June and July when the UV Index reaches an extreme level of 11, with a burn time of just 10 minutes. During these months, residents and visitors should take extra precautions, such as seeking shade, wearing protective clothing, and applying sunscreen regularly, especially between 10 a.m. and 4 p.m. As the fall approaches, UV levels gradually decrease, but caution should still be exercised in September and early October when UV values remain elevated. Overall, ensuring proper skin protection is crucial during the high-risk periods to mitigate the dangers of UV exposure.
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 |
| Riley | 3 | 5 | 6 | 9 | 10 | 11 | 11 | 10 | 9 | 6 | 4 | 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 |