Last updated: August 1, 2025
Understanding the UV Index is crucial for residents of Waterloo, United States, where varying levels of ultraviolet exposure can significantly impact skin health. By keeping track of UV levels, you can effectively prevent sunburns and reduce the risk of long-term skin damage. With a Dfb climate, Waterloo experiences distinct seasonal variations that can influence UV radiation intensity, particularly during summer months when peak values soar to 10 around midday. Stay informed and protect your skin by learning how to navigate the UV Index effectively!
As the day unfolds, the UV Index experiences a dramatic rise, peaking at an intense 10 around 1 PM, signaling the highest level of harmful UV radiation. Early morning hours start gently, with a maximum of 1 at 7 AM, gradually increasing to a moderate 4 by 9 AM. The ascent continues steadily, reaching a notable 8 between 11 AM and 12 PM before soaring to its zenith. After this peak, the index begins to wane, declining to 5 by 4 PM and dropping further to a safe 1 by 7 PM. It’s vital to stay protected during the peak hours of 11 AM to 3 PM to enjoy the sunshine without compromising skin health.
| 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, the UV Index shows significant seasonal changes that impact sun safety for residents and visitors. From April to September, the UV Index peaks, reaching levels as high as 10 in the summer months of June and July. This indicates a very high exposure category, with a reduced burn time of only 15 minutes during these months. Conversely, during the winter months of December through February, the UV Index is considerably lower, ranging from 2 to 4, with a burn time of 30 to 45 minutes. Therefore, visitors and residents should be especially cautious during the high-risk months of April to September, and take appropriate protective measures, such as wearing sunscreen, protective clothing, and seeking shade, to minimize their risk of UV exposure.
UV Risk Categories
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Waterloo | 3 | 4 | 5 | 8 | 9 | 10 | 10 | 9 | 8 | 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 |