Last updated: June 2, 2025
Awareness of the UV Index is crucial for residents of Lewiston, United States, as it helps safeguard skin health and prevent sunburn. Understanding UV levels is essential not only for enjoying the outdoors safely but also for reducing long-term health risks associated with sun exposure. With Lewiston's Csb climate, the UV Index can soar, especially during midday hours, reaching a peak of 11 around noon. This emphasizes the importance of taking protective measures during peak sunlight hours to enjoy the beautiful Pacific Northwest without compromising skin health.
The UV Index throughout the day showcases a steady increase as the sun climbs, peaking at an intense 11 between 12:00 PM and 2:00 PM. Early morning hours start at a mild 1 at 7:00 AM, gradually rising to 4 by 9:00 AM. As the clock strikes 10:00 AM, the index reaches 6, marking the onset of higher UV levels. From 11:00 AM, the sun’s intensity ramps up significantly, hitting 9 and holding steady at 11 during the peak afternoon hours. As shadows lengthen after 2:00 PM, the UV Index dips, descending to 9 at 3:00 PM, and gradually falling to 2 by the evening. Remember to stay protected during peak hours for optimal sun safety!
| 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 | 9 | very high | 15 min |
| 12:00 | 11 | extreme | 10 min |
| 13:00 | 11 | extreme | 10 min |
| 14:00 | 11 | extreme | 10 min |
| 15:00 | 9 | very high | 15 min |
| 16:00 | 7 | high | 25 min |
| 17:00 | 4 | moderate | 30 min |
| 18:00 | 2 | low | 45 min |
| 19:00 | 1 | low | 45 min |
Seasonal UV changes show a significant increase from winter to summer, peaking in May, June, and July with an extreme UV Index of 11 and a burn time of just 10 minutes. Notably, April marks the transition to very high levels at 9, while March reaches a high level of 7. August and September continue with very high ratings of 10 and 9 respectively, indicating continued caution is needed during these months. High-risk months for UV exposure, therefore, are April through September, when the UV Index is consistently high to extreme. Visitors and residents should take proper precautions, including wearing sunscreen, protective clothing, and seeking shade during peak sun hours, especially between 10 AM and 4 PM. As the year progresses towards fall and winter, UV levels decrease, returning to a moderate level (3-5), but vigilance remains important for skin protection at any time of the year.
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 |
| Lewiston | 3 | 5 | 7 | 9 | 11 | 11 | 11 | 10 | 9 | 6 | 4 | 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 |