Last updated: June 2, 2025
Understanding the UV Index is crucial for residents of Iowa, where sun exposure can pose significant risks to skin health. The UV Index provides vital information about the strength of solar radiation and helps individuals take proactive measures to prevent sunburn and long-term skin damage. With Iowa's humid continental climate, summers can see intense UV levels peaking at 12 during midday—highlighting the importance of being aware of daily UV variations. By staying informed about the UV Index, Iowans can enjoy the outdoors safely while protecting their skin from harmful rays.
The UV Index reveals a dynamic shift throughout the day, starting from a gentle 1 at 7:00 AM and climbing steadily to a peak of 12 at 1:00 PM. Between 10:00 AM and 2:00 PM, sun exposure is most intense, with values reaching 9 and 11, making it crucial for outdoor activities to come with protective measures. As the afternoon progresses, the index begins to decline, offering relief with readings of 9 at 3:00 PM, 7 at 4:00 PM, and tapering off to 2 by 6:00 PM. For evening relaxation, the UV Index settles back to a minimal 1 by 7:00 PM, providing a gentle close to the day's solar intensity.
| 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 | 9 | very high | 15 min |
| 12:00 | 11 | extreme | 10 min |
| 13:00 | 12 | extreme | 10 min |
| 14:00 | 11 | extreme | 10 min |
| 15:00 | 9 | very high | 15 min |
| 16:00 | 7 | high | 25 min |
| 17:00 | 4 | moderate | 30 min |
| 18:00 | 2 | low | 45 min |
| 19:00 | 1 | low | 45 min |
Throughout the year, the UV Index experiences significant fluctuations, peaking in the summer months. From January (UV Index 5) to February (UV Index 8), there's a clear increase, with March and April maintaining high levels (UV Index 9-10). May through August sees the highest readings, particularly reaching UV Index 12 in June and July, indicating extreme exposure risk, where skin can burn within just 10 minutes. As the year transitions to September and October, the UV Index begins to decline but remains in the very high category until November (UV Index 6) and finally returns to moderate in December. Visitors and residents should be particularly cautious between February and August—the high-risk months for UV exposure—by implementing protective measures such as wearing sunscreen, sunglasses, and hats, and seeking shade during peak sun hours.
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 |
| Los Angeles UVI | 4 | 6 | 8 | 9 | 10 | 11 | 11 | 10 | 10 | 7 | 5 | 4 |
| Iowa | 5 | 8 | 9 | 10 | 11 | 12 | 12 | 11 | 10 | 8 | 6 | 5 |
| Houston UVI | 5 | 8 | 9 | 11 | 11 | 12 | 12 | 11 | 10 | 9 | 7 | 5 |