September weather forecast
Allendale, NJ

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Weather in September

The first month of the autumn, September, is also a moderately hot month in Allendale, New Jersey, with an average temperature fluctuating between 75.2°F (24°C) and 58.3°F (14.6°C).

Temperature

The transition into September is accompanied by a slight temperature decrease, with the average high-temperature shifting from a warm 82.9°F (28.3°C) in August to a still moderately hot 75.2°F (24°C). In Allendale, the September nights cool down to an average low of 58.3°F (14.6°C).

Humidity

In Allendale, the average relative humidity in September is 74%.

Rainfall

September is the month with the least rainfall. Rain falls for 12.9 days and accumulates 1.89" (48mm) of precipitation.

Snowfall

May through September are months without snowfall.

Daylight

In Allendale, the average length of the day in September is 12h and 28min.
On the first day of the month, sunrise is at 6:23 am and sunset at 7:28 pm. On the last day of September, sunrise is at 6:52 am and sunset at 6:39 pm EDT.

Sunshine

In September, the average sunshine 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 health risk from unprotected exposure to Sun's UV rays for the average person.
Note: The UV index of 4 in September translates into these instructions:
Exercise caution. Those with pale skin may experience burns in less than half an hour. When the Sun's UV radiation is most intense during midday, it's best to find shade and limit exposure. A hat with a broad brim is indispensable, filtering out up to half of UV rays.
Updated: Jul 12, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the temperature in September?

The average high-temperature, in September, in Allendale, is 75.2°F (24°C), while the average low-temperature is 58.3°F (14.6°C). The average heat index (a.k.a. 'apparent temperature', 'feels like'), which combines air temperature and relative humidity, in August is computed to be 87.8°F (31°C).

What is the average humidity in September?

The average relative humidity in September is 74%.

What is the driest month?

September is the month with the least rainfall. Rain falls for 12.9 days and accumulates 1.89" (48mm) of precipitation.

How many days does it rain in September?

In Allendale, in September, during 12.9 rainfall days, 1.89" (48mm) of precipitation is typically accumulated.

When it does not snow?

In Allendale, snow does not fall in May through September.

Does it snow in September?

In Allendale, in September, it doesn't snow. In October, it regularly snows.

How many hours of daylight does Allendale have in September?

In Allendale, the average day length in September is 12h and 28min.

When is the sunrise / sunset in September?

On the first day of September, sunrise is at 6:23 am and sunset at 7:28 pm. On the last day of the month, sunrise is at 6:52 am and sunset at 6:39 pm EDT.

How many hours of sunshine does Allendale have in September?

In Allendale, the average sunshine duration in September is 8.5h.

What is the UV index reading in September in Allendale?

The average daily maximum UV index in September is 4. A UV Index value of 3 to 5 symbolizes a medium hazard to health from unprotected exposure to UV radiation.
Average humidity
Average rainfall days
Average snowfall
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in September
Allendale, NJ

Average temperature in September - Allendale, NJ
  • Average high temperature in September: 75.2°F

The warmest month (with the highest average high temperature) is July (84.7°F).
The month with the lowest average high temperature is January (35.2°F).

  • Average low temperature in September: 58.3°F

The month with the highest average low temperature is July (66.6°F).
The coldest month (with the lowest average low temperature) is January (22.8°F).

Average pressure in September
Allendale, NJ

Average pressure in September - Allendale, NJ
  • Average pressure in September: 30.06"Hg

The month with the highest atmospheric pressure is November (30.1"Hg).
The month with the lowest atmospheric pressure is June (29.93"Hg).

Average wind speed in September
Allendale, NJ

Average wind speed in September - Allendale, NJ
  • Average wind speed in September: 5.8mph

The windiest month (with the highest average wind speed) is March (8mph).
The calmest month (with the lowest average wind speed) is August (5.4mph).

Average humidity in September
Allendale, NJ

Average humidity in September - Allendale, NJ
  • Average humidity in September: 74%

The months with the highest relative humidity are February and December (78%).
The month with the lowest relative humidity is August (70%).

Average rainfall in September
Allendale, NJ

Average rainfall in September - Allendale, NJ
  • Average rainfall in September: 1.89"

The wettest month (with the highest rainfall) is December (3.58").
The driest month (with the least rainfall) is September (1.89").

Average rainfall days in September
Allendale, NJ

Average rainfall days in September - Allendale, NJ
  • Average rainfall days in September: 12.9 days

The months with the highest number of rainy days are May and July (16.8 days).
The month with the least rainy days is January (8.4 days).

Average snowfall in September
Allendale, NJ

Average snowfall in September - Allendale, NJ
  • Average snowfall in September: 0"

The month with the highest snowfall is February (4.09").
The months with the least snowfall are May, June, July, August and September (0").

Average snowfall days in September
Allendale, NJ

Average snowfall days in September - Allendale, NJ
  • Average snowfall days in September: 0 days

The month with the highest number of snowfall days is February (7.9 days).
The months with the least snowfall days are May, June, July, August and September (0 days).

Average daylight in September /
Average sunshine in September
Allendale, NJ

Average daylight in September / Average sunshine in September - Allendale, NJ
  • Average daylight in September: 12h and 3min

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 3min

The month with the most sunshine is July (Average sunshine: 10h and 12min).
The month with the least sunshine is February (Average sunshine: 4h and 30min).

Average sunshine days in September
Allendale, NJ

Average sunshine days in September - Allendale, NJ
  • Average sunshine days in September: 15.1 days

The month with the most sunshine days is November (18.7 days).
The month with the least sunshine days is June (11.5 days).

Average UV index in September
Allendale, NJ

Average UV index in September - Allendale, 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
Allendale, NJ

Average cloud cover in September - Allendale, NJ
  • Average cloud cover in September: 39

The month with the most cloud cover is March (Cloud cover 50).
The month with the least cloud cover is August (Cloud cover 34).

Average visibility in September
Allendale, NJ

Average visibility in September - Allendale, NJ
  • Average visibility in September: 6mi

The months with the highest visibility are January, February, March, April, June, July, August, September, October, November and December (6mi).
The month with the lowest visibility is May (5mi).

Allendale, New Jersey, USA

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