September Weather in Norwalk, United States

Last updated: June 24, 2025

In September, the average temperature in Norwalk, United States is a pleasant 23°C (74°F). Expect a comfortable range with minimums dipping to 12°C (54°F) and soaring to a hot 44°C (112°F). With an average humidity of 68% and a modest precipitation amount of 4 mm (0.1 in) across just 0 days, it's the perfect time to explore the area's vibrant attractions!

September Temperature in Norwalk

In September in Norwalk, the average temperature is 23°C (74°F). Maximum can reach 44°C (112°F) and minimum can be as low as 12°C (54°F). Be prepared for a wide temperature range and pack accordingly for your travels.

September Weather in Norwalk: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in Norwalk, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Norwalk, September typically has an average temperature of 23°C (74°F), with highs reaching up to 44°C (112°F) and lows dropping to around 12°C (54°F).

Data source: Temperature data for Norwalk generated using information from the Copernicus Climate Change Service.

September Precipitation in Norwalk

In Norwalk in September, the precipitation amount is 4 mm (0.1 in) recorded over a span of 0 days.

September Precipitation Trends in Norwalk

The chart displays monthly precipitation patterns in Norwalk, with values for each month alongside September’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how September’s conditions compare to those of other months. In Norwalk, September typically receives around 4 mm (0.1 inches) of precipitation spread over approximately 0 days.

Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.

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Millimeters (mm) Inches (in)

September Humidity in Norwalk

In Norwalk in September, humidity is 68%. With an average temperature of 23°C (74°F), this humidity feels like a warm embrace, making traveling quite uncomfortable if you're not prepared. The air is thick and muggy, leaving you yearning for a cool breeze and frequent breaks in the shade.

September Average Humidity in Norwalk

This chart illustrates the average monthly humidity levels in Norwalk, with September’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In September, average humidity in Norwalk is approximately 68%, offering insight into how humid the weather typically is during this month.

Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Norwalk

In Norwalk in September, the maximum UV index reaches 10, which corresponds to a very high Exposure Category. With a time to burn of just 15 minutes, it's crucial to take precautions. For more detailed information, you can check the Hourly UV Index in Norwalk.

Maximum UV Index Levels in Norwalk for September

The chart shows the monthly maximum UV Index (UVI) for Norwalk in September, representing the highest UV radiation level. The UVI measures the intensity of ultraviolet radiation from the sun, indicating the potential risk of sunburn and UV-related health issues. In September, the maximum UV index in Norwalk typically reaches 10, which falls under the very high exposure category.

Data source: Norwalk September UVI data generated using 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.

How September Weather in Norwalk Compares to Other Months

Weather in Norwalk varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in Norwalk, focusing on differences in temperature, rainfall, humidity, and UV levels.

This table compares monthly weather conditions in Norwalk, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	13°C (56°F)	75 mm (3.0 inches)	74%	moderate
February Weather	13°C (56°F)	63 mm (2.5 inches)	79%	high
March Weather	14°C (58°F)	67 mm (2.7 inches)	75%	very high
April Weather	17°C (63°F)	23 mm (0.9 inches)	70%	very high
May Weather	18°C (65°F)	16 mm (0.6 inches)	70%	very high
June Weather	21°C (70°F)	3 mm (0.1 inches)	72%	extreme
July Weather	24°C (76°F)	2 mm (0.1 inches)	73%	extreme
August Weather	25°C (76°F)	2 mm (0.1 inches)	69%	very high
September Weather	23°C (74°F)	4 mm (0.1 inches)	68%	very high
October Weather	20°C (69°F)	10 mm (0.4 inches)	67%	high
November Weather	17°C (62°F)	20 mm (0.8 inches)	68%	moderate
December Weather	13°C (56°F)	72 mm (2.8 inches)	71%	moderate