UV Index in Norwalk, United States

Last updated: July 2, 2025

Understanding the UV Index is crucial for residents and visitors of Norwalk, United States, where sun exposure can significantly affect your health. As our climate falls under the Cfa zone, the region experiences warm summers with varying levels of UV radiation throughout the day. Being aware of UV levels is essential for preventing sunburn and promoting healthy skin, particularly during peak hours when the index reaches a striking 9 around noon. Familiarizing yourself with these daily UV fluctuations can empower you to take proactive measures against harmful rays while enjoying your time outdoors in this vibrant city.

Hourly UV Index in Norwalk

The UV Index throughout the day presents a clear pattern of intensity, peaking at midday. Starting from a mild level of 1 at 07:00, the index rises steadily, reaching 2 by 08:00. The real surge occurs between 09:00 and 13:00, where it escalates from 4 to a striking 9—the highest point of the day. As the afternoon unfolds, the intensity slightly declines to 7 at 15:00, before tapering off to 5 at 16:00. The evening sees a further decrease, settling back to 2 by 18:00 and returning to 1 at 19:00. For those enjoying outdoor activities, it’s essential to take precautions, especially during the peak hours from 11:00 to 14:00 when the UV rays are most potent.

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	9	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 Norwalk

Throughout the year, the UV Index experiences notable fluctuations, with high-risk months typically spanning from March to September. In April and May, the Index peaks at 10, indicating a very high exposure category where the burn time is just 15 minutes. Consequently, during these months, it is crucial for both visitors and residents to take precautions such as wearing sunscreen, protective clothing, and sunglasses. The risk slightly diminishes in October with a UV Index of 6, shifting to lower levels by November and December, where the Index falls to 4 and 2, respectively. As the year progresses, individuals are encouraged to adjust their sun safety practices according to these seasonal changes to ensure their skin health remains a priority.

Monthly Maximum UV Index for Norwalk, United States

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

The table above highlights how UV exposure in Norwalk 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.

Norwalk'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
Norwalk	3	5	6	8	10	10	9	9	8	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