Last updated: June 2, 2025
In Portland, United States, being aware of the UV Index is crucial for maintaining skin health and preventing sunburn. Understanding UV levels can empower residents and visitors alike to safeguard themselves against harmful radiation, especially during peak hours when the risk is highest. With Portland's Dfb climate, characterized by warm summers and varying cloud cover, UV exposure can catch you off guard. From mid-morning to early afternoon, when the UV Index reaches levels 7 to 9, it’s essential to take protective measures to enjoy the sunshine safely!
Throughout the day, the UV Index fluctuates dramatically, peaking during the midday hours. Starting at a low of 1 at 07:00, the index rises steadily, reaching 3 by 09:00. As 10:00 approaches, it escalates to 5, but the real intensity hits between 12:00 and 14:00 when it peaks at 9. During this window, it's crucial to take sun safety precautions. As the afternoon progresses, the UV levels begin to taper off, dropping to 8 at 15:00 and gradually declining further to 3 by 18:00. Finally, the UV Index returns to its morning low of 1 by 19:00, marking a safe end to sun exposure for the day.
| 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 | 8 | very high | 15 min |
| 16:00 | 6 | high | 25 min |
| 17:00 | 4 | moderate | 30 min |
| 18:00 | 3 | moderate | 30 min |
| 19:00 | 1 | low | 45 min |
Throughout the year, the UV Index experiences notable fluctuations, impacting sun safety practices for both residents and visitors. From January to March, the UV levels are relatively low to moderate, with burn times ranging from 30 to 45 minutes. However, April marks the beginning of higher UV exposure, reaching a peak in May and June, where the index hits 9, classified as very high, and the burn time drops to just 15 minutes. July and August maintain these critical levels, posing significant risk for unprotected skin. September sees a decrease to a high index of 7, while October and November present moderate conditions again, allowing burn times of 30 minutes. By December, UV exposure returns to low levels. Visitors and residents are strongly advised to prioritize sun protection during the high-risk months of May through August, by applying sunscreen, seeking shade, and wearing protective clothing to minimize the risk of skin damage.
UV Risk Categories
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Portland | 2 | 4 | 5 | 7 | 8 | 9 | 9 | 8 | 7 | 4 | 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 |