September weather forecastNorwalk, CT
September
Weather in September
September in Norwalk ushers in the fall season, with temperatures retreating from the summer highs. High temperatures drop to 73°F (22.8°C) and low temperatures to 61.2°F (16.2°C), signaling the arrival of mild temperatures. The town begins to shift gears from the activities of summer to the tranquility of fall. Colorful foliage starts appearing, painting the scenery in shades of autumn.Temperature
Norwalk's progression into September involves a minor drop in the average high-temperature, slightly receding from a moderately hot 80.1°F (26.7°C) in August to a pleasant 73°F (22.8°C). During September, the nighttime temperature averages of 61.2°F (16.2°C).Humidity
The average relative humidity in September is 75%.Rainfall
In September, the rain falls for 13.4 days. Throughout September, 2.72" (69mm) of precipitation is accumulated. In Norwalk, during the entire year, the rain falls for 166.3 days and collects up to 37.87" (962mm) of precipitation.Snowfall
In Norwalk, snow does not fall in May through October.Ocean temperature
In Norwalk, the average seawater temperature in September is 68.7°F (20.4°C).Note: The majority of individuals do not enjoy swimming in water that is 68.7°F (20.4°C). Breathing control becomes more challenging as the water temperature dips from 69.8°F (21°C) to 59°F (15°C).
Daylight
In Norwalk, the average length of the day in September is 12h and 28min.On the first day of the month, sunrise is at 6:20 am and sunset at 7:25 pm. On the last day of September, sunrise is at 6:49 am and sunset at 6:36 pm EDT.
Sunshine
In Norwalk, the average sunshine in September is 8.9h.UV index
In Norwalk, Connecticut, the average daily maximum UV index in September is 4. A UV Index reading of 3 to 5 represents a medium vulnerability from unprotected exposure to Sun's UV rays for ordinary individuals.Note: In September, an average UV index of 4 transforms into the following instructions:
Put precautions into practice - Ensuring skin and eye safety is a necessity. Direct Sun exposure should be minimized especially during midday when radiation is most intense. Employ a wide-brim hat for potent defense against up to 50% of UV rays.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Norwalk, CT
- Average high temperature in September: 73°F
The warmest month (with the highest average high temperature) is July (81.1°F).
The month with the lowest average high temperature is January (35.8°F).
- Average low temperature in September: 61.2°F
The month with the highest average low temperature is July (68.2°F).
The coldest month (with the lowest average low temperature) is January (26.4°F).
Average pressure in September
Norwalk, CT
- Average pressure in September: 30.05"Hg
The month with the highest atmospheric pressure is November (30.09"Hg).
The month with the lowest atmospheric pressure is June (29.93"Hg).
Average wind speed in September
Norwalk, CT
- Average wind speed in September: 7.6mph
The windiest month (with the highest average wind speed) is January (10.1mph).
The calmest month (with the lowest average wind speed) is July (6.5mph).
Average humidity in September
Norwalk, CT
- Average humidity in September: 75%
The months with the highest relative humidity are February, May and June (76%).
The months with the lowest relative humidity are April and November (72%).
Average rainfall in September
Norwalk, CT
- Average rainfall in September: 2.72"
The wettest month (with the highest rainfall) is July (4.13").
The driest months (with the least rainfall) are January and February (2.36").
Average rainfall days in September
Norwalk, CT
- Average rainfall days in September: 13.4 days
The month with the highest number of rainy days is July (18.1 days).
The month with the least rainy days is January (8.3 days).
Average snowfall in September
Norwalk, CT
- Average snowfall in September: 0"
The month with the highest snowfall is February (2.83").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in September
Norwalk, CT
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is February (7.4 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average sea temperature in September
Norwalk, CT
- Average sea temperature in September: 68.7°F
The best month for swimming (with the highest average sea temperature) is August (73°F).
The coldest month (with the lowest average sea temperature) is February (39°F).
Average daylight in September /
Average sunshine in September
Norwalk, CT
- Average daylight in September: 12h and 30min
The month with the longest days is June (Average daylight: 15h and 6min).
The month with the shortest days is December (Average daylight: 9h and 18min).
- Average sunshine in September: 8h and 54min
The month with the most sunshine is July (Average sunshine: 10h and 30min).
The month with the least sunshine is February (Average sunshine: 4h and 42min).
Average sunshine days in September
Norwalk, CT
- Average sunshine days in September: 14 days
The month with the most sunshine days is January (17.8 days).
The month with the least sunshine days is June (10 days).
Average UV index in September
Norwalk, CT
- Average UV index in September: 4
The months with the highest UV index are June, July and August (UV index 6).
The months with the lowest UV index are January, February, March, November and December (UV index 2).
Average cloud cover in September
Norwalk, CT
- Average cloud cover in September: 34
The months with the most cloud cover are February, March and December (Cloud cover 48).
The month with the least cloud cover is August (Cloud cover 30).
Average visibility in September
Norwalk, CT
- Average visibility in September: 6mi
The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
