September weather forecastCedar Knolls, NJ
September
Weather in September
September, the first month of the autumn in Cedar Knolls, is also a moderately hot month, with an average temperature varying between 74.5°F (23.6°C) and 57.2°F (14°C).Temperature
Cedar Knolls's weather subtly changes with the onset of September, barely falling from a warm 81.5°F (27.5°C) in August to a still moderately hot 74.5°F (23.6°C). Throughout September, Cedar Knolls registers a consistent average low-temperature of 57.2°F (14°C).Humidity
In Cedar Knolls, the average relative humidity in September is 77%.Rainfall
The months with the least rainfall are January, February and September Rain falls for 12.9 days and accumulates 1.57" (40mm) of rain.Snowfall
In Cedar Knolls, snow does not fall in June through October.Daylight
In Cedar Knolls, the average length of the day in September is 12h and 27min.On the first day of September, sunrise is at 6:25 am and sunset at 7:29 pm. On the last day of the month, sunrise is at 6:54 am and sunset at 6:41 pm EDT.
Sunshine
In Cedar Knolls, the average sunshine in September is 8.5h.UV index
The average daily maximum UV index in September is 4. A UV Index estimate of 3 to 5 represents a moderate threat to health from exposure to the Sun's UV rays for ordinary individuals.Note: In September, a regular UV index of 4 translates into these guidelines:
Undertake protective steps - Preventing sun damage is advised. Direct Sun exposure should be minimized especially during midday when radiation is most intense. For effective sun eye protection, rely on sunglasses certified for UVA and UVB resistance.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Cedar Knolls, NJ
- Average high temperature in September: 74.5°F
The warmest month (with the highest average high temperature) is July (83.7°F).
The month with the lowest average high temperature is January (34.9°F).
- Average low temperature in September: 57.2°F
The month with the highest average low temperature is July (65.7°F).
The coldest month (with the lowest average low temperature) is January (22.5°F).
Average pressure in September
Cedar Knolls, NJ
- Average pressure in September: 30.06"Hg
The month with the highest atmospheric pressure is November (30.11"Hg).
The month with the lowest atmospheric pressure is June (29.93"Hg).
Average wind speed in September
Cedar Knolls, NJ
- Average wind speed in September: 5.8mph
The windiest month (with the highest average wind speed) is March (8.5mph).
The calmest month (with the lowest average wind speed) is August (5.3mph).
Average humidity in September
Cedar Knolls, NJ
- Average humidity in September: 77%
The months with the highest relative humidity are February, October and December (80%).
The month with the lowest relative humidity is April (74%).
Average rainfall in September
Cedar Knolls, NJ
- Average rainfall in September: 1.57"
The wettest month (with the highest rainfall) is July (3.19").
The driest months (with the least rainfall) are January, February and September (1.57").
Average rainfall days in September
Cedar Knolls, NJ
- Average rainfall days in September: 12.9 days
The month with the highest number of rainy days is May (18.3 days).
The month with the least rainy days is January (8.3 days).
Average snowfall in September
Cedar Knolls, NJ
- Average snowfall in September: 0"
The month with the highest snowfall is March (3.7").
The months with the least snowfall are June, July, August, September and October (0").
Average snowfall days in September
Cedar Knolls, NJ
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is February (6.8 days).
The months with the least snowfall days are June, July, August, September and October (0 days).
Average daylight in September /
Average sunshine in September
Cedar Knolls, NJ
- 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 30min
The month with the most sunshine is July (Average sunshine: 10h and 18min).
The month with the least sunshine is February (Average sunshine: 4h and 36min).
Average sunshine days in September
Cedar Knolls, NJ
- Average sunshine days in September: 15 days
The month with the most sunshine days is November (19 days).
The month with the least sunshine days is July (10.9 days).
Average UV index in September
Cedar Knolls, NJ
- 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
Cedar Knolls, NJ
- Average cloud cover in September: 40
The months with the most cloud cover are February, March and December (Cloud cover 49).
The months with the least cloud cover are July and August (Cloud cover 34).
Average visibility in September
Cedar Knolls, NJ
- Average visibility in September: 5mi
The months with the highest visibility are January, February, March, April, July, August, October, November and December (6mi).
The months with the lowest visibility are May, June and September (5mi).





