Last updated: July 2, 2025
In Waterloo, United States, staying informed about the UV Index is crucial for protecting your skin and overall health. Understanding UV levels can help you take proactive measures against sunburn and minimize long-term skin damage. With a Dfb climate, Waterloo experiences a range of UV exposure throughout the day, peaking at an intensity of 9 between noon and 2 PM. Being aware of these fluctuations can empower you to enjoy the outdoors safely while safeguarding your skin from harmful UV rays.
The UV Index for the day showcases a notable rise in intensity as the sun climbs higher in the sky. Starting at a low of 1 at 7:00 AM, the index gradually increases to a moderate level of 3 by 9:00 AM. However, from 10:00 AM onward, things heat up significantly, peaking at a scorching 9 from noon to 2:00 PM. As the afternoon progresses, the UV Index gradually dips back to a friendly 3 by 5:00 PM, then descends further to 1 by the time evening sets in. This pattern underscores the importance of sun protection during peak hours, especially between 11:00 AM and 2:00 PM, when UV levels are at their highest.
| 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 | 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 |
Throughout the year, the UV Index exhibits significant seasonal variations that are crucial for residents and visitors to understand. January and December mark the lowest UV exposure levels (Index 2), where sunburn risk is minimal, allowing for longer burn times of about 45 minutes. As spring approaches, February sees a moderate increase with an Index of 4 (30 min burn time), leading into a high-risk period beginning in March with an Index of 6 and continuing to peak from April to June at 10 (15 min burn time). The summer months of July and August remain dangerously high with an Index of 9 (15 min burn time). As autumn arrives, risks decrease, but September and October still present high levels (Index 7 and 6 respectively, with 25 min burn times). Finally, November reverts to moderate levels (Index 3), before returning to low exposure in January. Visitors and residents are advised to take extra precautions during the high-risk months of April through August, such as applying sunscreen, wearing protective clothing, and seeking shade to minimize harmful UV exposure.
UV Risk Categories
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Waterloo | 2 | 4 | 6 | 8 | 10 | 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 |