September Weather in Norwalk, United States

Last updated: June 24, 2025

In September, the average temperature in Norwalk, United States is a pleasant 20°C (68°F). You can expect a minimum of 7°C (45°F) and a maximum of 32°C (89°F). During this time, the region experiences approximately 81 mm (3.2 in) of precipitation over 9 days, contributing to an average humidity of 78%. Ideal for exploring the beauty of Norwalk while enjoying a comfortable climate!

September Temperature in Norwalk

In September in Norwalk, the average temperature is 20°C (68°F). Maximums can reach 32°C (89°F), while minimums can drop as low as 7°C (45°F). It's a great time to visit for pleasant weather and outdoor activities.

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 20°C (68°F), with highs reaching up to 32°C (89°F) and lows dropping to around 7°C (45°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 81 mm (3.2 in) spread over a duration of 9 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 81 mm (3.2 inches) of precipitation spread over approximately 9 days.

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

Choose your preferred precipitation unit

Millimeters (mm) Inches (in)

September Humidity in Norwalk

In Norwalk in September humidity is 78%. With an average temperature of 20°C (68°F), this humidity feels like a warm, enveloping blanket that makes exploring the sights a bit sticky, so travelers should stay hydrated and take 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 78%, 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 is 8, which corresponds to a very high Exposure Category. This means that the time to burn is only 15 minutes. For more detailed information, you can refer to 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 8, 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	-1°C (30°F)	83 mm (3.3 inches)	88%	moderate
February Weather	0°C (32°F)	95 mm (3.7 inches)	87%	moderate
March Weather	4°C (39°F)	99 mm (3.9 inches)	87%	high
April Weather	9°C (49°F)	120 mm (4.7 inches)	87%	very high
May Weather	16°C (61°F)	129 mm (5.1 inches)	81%	very high
June Weather	21°C (70°F)	124 mm (4.9 inches)	82%	very high
July Weather	24°C (75°F)	124 mm (4.9 inches)	81%	very high
August Weather	23°C (73°F)	86 mm (3.4 inches)	78%	very high
September Weather	20°C (68°F)	81 mm (3.2 inches)	78%	very high
October Weather	14°C (58°F)	105 mm (4.2 inches)	82%	high
November Weather	5°C (42°F)	99 mm (3.9 inches)	89%	moderate
December Weather	2°C (35°F)	87 mm (3.4 inches)	86%	low