Last updated: June 2, 2025
Understanding the UV Index is essential for residents and visitors in Lisbon, United States, where the climate brings both sunny days and potential sunburn risks. The UV Index provides crucial information on the strength of ultraviolet radiation, helping you make informed decisions to protect your skin health and prevent sunburn. With typical summer highs peaking at a UV Index of 11 around midday, the risk of overexposure increases significantly. Lisbon's Dfa climate contributes to these elevated UV levels, making it important to stay aware and take necessary precautions to enjoy the outdoors safely. Whether you're planning a day in the park or just stepping outside, knowing the UV Index can help you safeguard your skin and overall health.
The UV Index throughout the day follows a predictable rise and fall, peaking at 11 around 1:00 PM. Starting at a modest 1 at 7:00 AM, it gradually escalates, reaching 10 by 12:00 PM, signaling the need for sun protection. As the afternoon progresses, the index dips from 11 to 8 by 3:00 PM, then declines further to 2 by 6:00 PM, and finally settles back at 1 by 7:00 PM. This data underscores the importance of taking precautions during the hours of peak UV exposure, particularly between 11:00 AM and 3:00 PM, when levels are highest and pose the greatest risk to skin health.
| 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 | 10 | very high | 15 min |
| 13:00 | 11 | extreme | 10 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 |
Throughout the year, the UV Index exhibits notable fluctuations, with high-risk months typically falling between April and September. During this period, the UV Index peaks in June at a severe level of 11, signifying an extreme exposure category with a burn time of just 10 minutes. Following closely are May and July, both rated as very high with indices of 9 and 10 respectively, while April and August maintain a very high category as well, with indices reaching 8. As winter approaches, the UV Index drops to a moderate level in January, February, November, and December, offering safer exposure times of up to 30 minutes. To protect yourself during peak UV times, especially from April to September, it's crucial to apply sunscreen regularly, wear protective clothing, and limit sun exposure during mid-day hours.
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 |
| Lisbon | 3 | 5 | 6 | 8 | 9 | 11 | 10 | 9 | 8 | 6 | 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 |