Last updated: June 2, 2025
In Waterloo, United States, being aware of the UV Index is crucial for protecting your skin and health. Understanding UV levels can significantly reduce the risk of sunburn and long-term skin damage, making it essential knowledge for residents and visitors alike. With a climate characterized by warm summers typical of the Dfb zone, Waterloo experiences peak UV exposure, especially around midday when levels can reach a high of 10. By staying informed about UV trends throughout the day, you can enjoy the outdoors safely while taking proactive steps to maintain your skin health.
From 07:00 to 08:00, the UV Index starts off mild with a maximum of 1 to 2, making it a safe time for early outdoor activities. As the sun climbs higher, the UV levels rise sharply, reaching 4 by 09:00 and hitting 6 by 10:00. The intensity peaks at 13:00 with a significant 10, indicating high exposure risk, perfect for applying sunscreen and seeking shade. As we move into the afternoon, levels gradually decrease, tapering to 9 by 14:00 and falling back to a more manageable 4 by 17:00. By evening, UV levels drop to 2 at 18:00 and retreat to 1 by 19:00, marking a safe return for those looking to enjoy twilight outdoors. Remember, it's essential to stay vigilant during those peak hours!
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 1 | low | 45 min |
| 08:00 | 2 | low | 45 min |
| 09:00 | 4 | moderate | 30 min |
| 10:00 | 6 | high | 25 min |
| 11:00 | 8 | very high | 15 min |
| 12:00 | 9 | very high | 15 min |
| 13:00 | 10 | very high | 15 min |
| 14:00 | 9 | very high | 15 min |
| 15:00 | 8 | very high | 15 min |
| 16:00 | 6 | 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 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 |