UV Index in Acton, United States

Last updated: July 2, 2025

Understanding the UV Index is essential for residents of Acton, United States, where varying levels of UV radiation can pose risks, especially during the sunny summer months in this Dfb climate zone. By keeping an eye on UV levels, you can better protect yourself from painful sunburns and reduce the long-term risks of skin damage and conditions like skin cancer. With maximum UV Index values peaking at 9 midday, it's crucial to be aware of when the sun's rays are strongest and to take protective measures for your skin health.

Hourly UV Index in Acton

The UV Index today presents a notable climb as the sun ascends, peaking at 9 around noon and early afternoon, signaling very high sun exposure risk. Starting gently at 1 by 7 AM, the index rises steadily, reaching 6 by 10 AM and then surging to its maximum of 9 between 12 PM and 1 PM. Early afternoon brings a slight decline to 8 at 2 PM, followed by a gradual decrease through the later hours, settling back to 1 by 7 PM. With this trajectory, it's crucial to take precautions during the peak hours of 11 AM to 1 PM, ensuring skin protection against harmful UV rays. Stay safe and enjoy the sun wisely!

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	4	moderate	30 min
10:00	6	high	25 min
11:00	8	very high	15 min
12:00	9	very high	15 min
13:00	9	very high	15 min
14:00	8	very high	15 min
15:00	7	high	25 min
16:00	5	moderate	30 min
17:00	3	moderate	30 min
18:00	2	low	45 min
19:00	1	low	45 min

Monthly UV Index Trends in Acton

The UV Index exhibits notable seasonal changes throughout the year, with high-risk months primarily occurring from April to August, when the index reaches very high levels (8-10) and a burn time of just 15 minutes is recommended. Specifically, April through July are critical periods, with May and June experiencing the highest values. During these months, it is essential for visitors and residents to take precautions such as wearing sunscreen, protective clothing, and sunglasses, and seeking shade during peak sun hours. Conversely, January and December present lower risks with a UV Index of 2-3, allowing for more extended sun exposure of up to 45 minutes and only moderate protection needed. Overall, staying informed of the UV Index can help ensure safety and enjoyment while outdoors year-round.

Monthly Maximum UV Index for Acton, United States

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

The table above highlights how UV exposure in Acton 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.

Acton'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
Acton	3	5	6	8	9	10	9	9	7	6	4	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