Last updated: May 3, 2025
Understanding the UV Index is crucial for residents and visitors in Waterloo, United States, where the Dfb climate can bring varying levels of sun exposure throughout the year. Being aware of UV levels helps in taking essential precautions against sunburn and long-term skin health issues, allowing you to enjoy the outdoors safely. During peak hours—particularly between 11:00 AM and 1:00 PM—UV Index values can reach a high of 10, highlighting the need for protective measures like sunscreen and clothing. As you navigate Waterloo's beautiful sunny days, staying informed about UV risks can enhance your outdoor experiences while safeguarding your skin.
As the sun rises, the UV Index starts its ascent, with a gentle 1 at 07:00. By 08:00, it begins to climb, reaching 2, signaling a reminder to take care. The real intensity kicks in at 10:00, where the index peaks at 6, escalating to a scorching 9 by noon. The hottest moment arrives at 13:00, showcasing a dramatic 10—a level that demands serious sun protection. Although the UV level begins to drop after this peak, it remains notable; at 14:00, it settles at 9, then declines gently, hitting 3 by 17:00. As daylight fades towards the evening, it tapers off to 2 at 18:00 and finally returns to a safe 1 by 19:00. It's a vivid reminder of the sun's power throughout the day!
| 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 | 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 |