Last updated: July 2, 2025
Understanding the UV Index is crucial for residents of Waterloo, United States, where sunny days invite both enjoyment and caution. As you navigate the region's Dfa climate, be aware that UV levels can reach as high as 10 around midday, making sun protection essential to prevent painful sunburns and long-term skin health issues. By staying informed about the UV Index, you can enjoy the outdoors safely while minimizing the risks associated with overexposure to harmful ultraviolet rays. With the right precautions, you can soak up the sun without compromising your skin's well-being.
The UV Index reveals a dynamic ascent and descent throughout the day, peaking with intensity during midday. Starting at a gentle 1 at 7:00 AM, it climbs steadily, reaching 10 by 1:00 PM and maintaining this highest level until 2:00 PM. This critical window indicates significant sun exposure, and it’s essential to take precautions. As the afternoon progresses, the index begins to taper off, dropping to 8 at 3:00 PM, then gradually falling to 1 by 7:00 PM. This data highlights the importance of being sun-smart during the peak hours to minimize UV exposure risks.
| 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 | 8 | very high | 15 min |
| 12:00 | 9 | very high | 15 min |
| 13:00 | 10 | very high | 15 min |
| 14:00 | 10 | 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 |
The UV Index demonstrates significant seasonal variation throughout the year, peaking during the summer months. Notably, June reaches an extreme UV Index of 11, with a burn time of just 10 minutes, making it the highest risk period. May and July also have very high levels, at 9 and 10 respectively, with a burn time of 15 minutes. The spring months see a steady increase, with April at 8 and a burn time of 15 minutes, while March escalates to a high level with a burn time of 25 minutes. By contrast, January, February, October, November, and December display a moderate UV Index, typically allowing for a burn time of 30 minutes. Accordingly, visitors and residents should exercise caution, especially from March through September, when UV levels are notably higher. Regular use of sunscreen, protective clothing, and limiting sun exposure during peak hours is recommended to safeguard against skin damage.
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 |
| Waterloo | 3 | 5 | 6 | 8 | 9 | 11 | 10 | 9 | 8 | 5 | 3 | 3 |
| 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 |