UV Index in Northwest, United States

Last updated: July 2, 2025

Understanding the UV Index is crucial for residents in the Northwest, United States, where varying weather patterns can significantly affect sun exposure. With UV levels reaching as high as 11 during peak hours, awareness is key to preventing sunburn and protecting skin health. The Northwest's Cfa climate means that cloudy days can still expose you to harmful UV rays, making it vital to stay informed about daily fluctuations in UV intensity. By keeping an eye on the UV Index, you can enjoy the outdoors safely while safeguarding your skin against potential damage.

Hourly UV Index in Northwest

The UV Index for the day showcases a dramatic rise in intensity as the sun climbs higher in the sky. Starting from a mild 1 at 07:00, it escalates steadily to a peak of 11 between 13:00 and 14:00, making it crucial to prioritize sun safety during these hours. As noon approaches, protective measures become essential with the index hitting a striking 10 at 12:00. Following that, a gradual decline occurs, retreating to 6 at 16:00, then tapering to 2 by 18:00 and settling back to 1 by 19:00. This pattern emphasizes the importance of seeking shade and wearing sunscreen during the midday hours when UV exposure is at its highest.

Average solar exposure data for the current time of the year. Actual values may vary and depend on many factors, such as cloud cover, vegetation cover, surface type, etc.
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	10	very high	15 min
13:00	11	extreme	10 min
14:00	11	extreme	10 min
15:00	9	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

Monthly UV Index Trends in Northwest

Throughout the year, UV index values fluctuate significantly, with peaks during the summer months. From January to March, the UV index rises from a moderate level of 4 to a very high 8, indicating an increasing risk for skin damage. The high-risk months are clearly identified as May through July, with an extreme index of 11, where the burn time shortens to just 10 minutes. This intensity decreases slightly in August and September but remains very high at 10 and 9, respectively. As the year closes, UV levels drop back to moderate levels by December. Visitors and residents should take precautions during the high-risk months by using sunscreen, wearing protective clothing, and seeking shade to minimize the risk of sunburn and long-term skin damage.

Monthly Maximum UV Index for Northwest, United States

The monthly maximum UV Index (UVI) represents the highest UV radiation level recorded each month in Northwest. It measures the strength of ultraviolet radiation from the sun and helps assess the risk of sunburn and UV-related health issues.

Data source: Statistical UV Index data for Northwest, based on information from the Copernicus Climate Change Service.

UV Risk Categories

Extreme (11+): Avoid the sun, stay in shade.
Very High (8-10): Limit sun exposure.
High (6-7): Use SPF 30+ and protective clothing.
Moderate (3-5): Midday shade recommended.
Low (0-2): No protection needed.

Compare Northwest UV Index with Other United States Cities

The table above highlights how UV exposure in Northwest compares to other major locations across United States. This comparison helps travelers and residents better understand regional sun intensity and plan outdoor activities with sun safety in mind.

Northwest's solar exposure compared to other cities in United States. Generated using Copernicus Atmosphere Monitoring Service information.
	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
Los Angeles UVI	4	6	8	9	10	11	11	10	10	7	5	4
Northwest	4	6	8	10	11	11	11	10	9	8	6	4
Houston UVI	5	8	9	11	11	12	12	11	10	9	7	5