Last updated: May 3, 2025
Understanding the UV Index is essential for residents of Monrovia, United States, as it plays a crucial role in protecting our skin and overall health. The risks of sunburn and long-term skin damage escalate significantly with rising UV levels, making it vital to stay informed about daily exposure. With Monrovia's Cfa climate characterized by warm summers and moderate sunlight, knowing when UV levels peak—particularly between 11:00 AM and 2:00 PM when indexes can reach as high as 10—is key to safeguarding yourself and your family from harmful effects. Stay informed, stay safe, and enjoy the sunshine wisely!
As the sun rises, the UV Index begins its gentle climb, starting at a modest 1 at 7:00 AM and 8:00 AM. By 9:00 AM, it nudges up to a 2, signaling the day is warming up. However, the intensity ramps up dramatically around 10:00 AM, peaking at 9 by 12:00 PM. The highest alert comes at 1:00 PM and 2:00 PM with a striking 10, indicating it’s time to seek shade and protect your skin. As the afternoon unfolds, the index recedes slowly, dropping to 5 by 5:00 PM and settling down to a safe 1 by 7:00 PM. Keep in mind, during peak hours, the sun's rays are most potent—stay safe and enjoy the sunshine wisely!
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 1 | low | 45 min |
| 08:00 | 1 | low | 45 min |
| 09:00 | 2 | low | 45 min |
| 10:00 | 4 | moderate | 30 min |
| 11:00 | 7 | high | 25 min |
| 12:00 | 9 | very high | 15 min |
| 13:00 | 10 | very high | 15 min |
| 14:00 | 10 | very high | 15 min |
| 15:00 | 9 | very high | 15 min |
| 16:00 | 7 | high | 25 min |
| 17:00 | 5 | moderate | 30 min |
| 18:00 | 3 | moderate | 30 min |
| 19:00 | 1 | low | 45 min |
As the seasons shift, the UV Index reveals a significant increase in ultraviolet radiation, particularly from March to September, indicating a heightened risk of sunburn and skin damage. The high-risk months are clearly defined from April to August, with the peak reaching a UV Index of 11 in June. During these times, the exposure category escalates to very high or extreme, resulting in a burn time as short as 10 minutes. Visitors and residents are strongly advised to take precautionary measures by wearing protective clothing, applying sunscreen, and seeking shade, especially during midday hours when the sun's intensity is at its peak. As the UV Index decreases in the fall and winter months, maintaining awareness and protection remains essential to ensure skin health year-round.
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 |
| Monrovia | 3 | 5 | 7 | 9 | 10 | 11 | 10 | 9 | 8 | 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 |