UV Index in Williamstown, United States

Last updated: July 2, 2025

Understanding the UV Index is vital for residents and visitors of Williamstown, United States, where the climate offers both beautiful sunny days and potential risks of overexposure to ultraviolet radiation. With typical UV Index levels peaking at 10 during midday, awareness of these UV ratings is essential for preventing sunburn and protecting skin health. As Williamstown experiences a Cfa climate, characterized by warm summers, it's crucial to recognize when UV levels are at their highest, ensuring that you take necessary precautions to enjoy the sun safely.

Hourly UV Index in Williamstown

The UV Index rises swiftly throughout the morning, starting from a low of 1 at 07:00 and climbing steadily to reach its peak of 10 at 13:00. As the sun reaches its zenith, the index hits 9 at 12:00, a clear reminder of the intense midday sun. After this high, the UV levels gradually decrease; by 15:00, they drop to 8 and continue to soften to 3 by 17:00, before safely settling back to a 1 at 19:00. It's essential to stay protected during those peak hours, particularly between 11:00 and 14:00, when the sun’s rays can be most dangerous. Remember to apply sunscreen and wear protective clothing to keep your skin safe while enjoying the outdoors!

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	9	very high	15 min
13:00	10	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	3	moderate	30 min
18:00	2	low	45 min
19:00	1	low	45 min

Monthly UV Index Trends in Williamstown

Throughout the year, UV exposure varies significantly, peaking during late spring and summer months. High-risk months for UV exposure are April through September, where the UV Index frequently reaches levels classified as very high; particularly notable are May, June, and July, when it consistently hits a maximum of 10. Visitors and residents are advised to take precautions during these months, with burn times dramatically reduced to as little as 15 minutes. In contrast, January, February, and November present moderate UV levels, and December has a low index, making sun safety measures less critical during these months. To protect against skin damage, it is essential to wear sunscreen, seek shade, and wear protective clothing, especially between peak months of April and September.

Monthly Maximum UV Index for Williamstown, United States

The monthly maximum UV Index (UVI) represents the highest UV radiation level recorded each month in Williamstown. 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 Williamstown, 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 Williamstown UV Index with Other United States Cities

The table above highlights how UV exposure in Williamstown 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.

Williamstown'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
Williamstown	3	5	6	9	10	10	10	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