September weather forecast and climate
Summit, NJ

The first month of the autumn, September, is also a moderately hot month in Summit, New Jersey, with average temperature varying between 57.6°F (14.2°C) and 74.5°F (23.6°C).

Temperature

In September, the average high-temperature marginally drops, from 81.9°F (27.7°C) in August, to a still warm 74.5°F (23.6°C). In Summit, the average low-temperature is 57.6°F (14.2°C).

Humidity

In September, the average relative humidity is 77%.

Rainfall

The month with the least rainfall in Summit, New Jersey, is September when the rain falls for 13.5 days and typically collects 1.69" (43mm) of precipitation.

Snowfall

June through September are months without snowfall in Summit.

Daylight

The average length of the day in Summit is 12.4h.

Sunshine

In Summit, New Jersey, the average sunshine in September is 8.5h.

UV index

In Summit, New Jersey, the average daily maximum UV index is 4. A UV Index value of 3 to 5 symbolizes a medium health hazard from unprotected exposure to the Sun's UV rays for the ordinary person.
Note: The average daily UV index of 4 transform into the following instructions:
Take precautions - Protection against sunburn is recommended. The solar radiation is most powerful near the mid-day, so the exposure to the direct Sun should be reduced accordingly. On bright days sunglasses that block both UVA and UVB rays should be worn. A hat with a wide brim is extremely helpful, as it can prevent roughly 50% of UV radiation from reaching the eyes.

What is the temperature in September in Summit?

In Summit, in September, the average high-temperature is 74.5°F (23.6°C), and the average low-temperature is 57.6°F (14.2°C).

What is the average humidity in September in Summit?

In September, the average relative humidity in Summit is 77%.

How many days does it rain in September in Summit?

In September, in Summit, the rain falls for 13.5 days. Throughout September, 1.69" (43mm) of precipitation is accumulated.

What is the driest month in Summit?

September is the month with the least rainfall. Rain falls for 13.5 days and accumulates 1.69" (43mm) of precipitation.

Does it snow in Summit in September?

In Summit, New Jersey, in September, it doesn't snow. In October, it regularly snows.

When it does not snow in Summit?

June through September are months without snowfall in Summit.

How many hours of daylight does Summit have in September?

In Summit, New Jersey, the average length of the day in September is 12.4h.

How many hours of sunshine does Summit have in September?

The average sunshine in September in Summit is 8.5h.

What is the UV index intensity in September in Summit?

In Summit, New Jersey, the average daily maximum UV index in September is 4. A UV Index estimate of 3 to 5 represents a medium health risk from the exposure to the Sun's UV rays.
Average temperature in September - Summit, 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 (35.1°F).

  • Average low temperature in September: 57.6°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 - Summit, NJ
  • Average pressure in September: 30.06"

The month with the highest atmospheric pressure is November (30.11").
The month with the lowest atmospheric pressure is June (29.93").

Average wind speed in September - Summit, 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 - Summit, NJ
  • Average humidity in September: 77%

Months with the highest relative humidity are February and December (80%).
Months with the lowest relative humidity are April and August (74%).

Average rainfall in September - Summit, NJ
  • Average rainfall in September: 1.69"

The wettest month (with the highest rainfall) is July (3.27").
The driest month (with the least rainfall) is September (1.69").

Average rainfall days in September - Summit, NJ
  • Average rainfall days in September: 13.5 days

The month with the highest number of rainy days is July (17.4 days).
The month with the least rainy days is January (8.8 days).

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

The month with the highest snowfall is March (3.5").
Months with the least snowfall are June, July, August and September (0").

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

The month with the highest number of snowfall days is January (7.6 days).
Months with the least snowfall days are June, July, August and September (0 days).

Average daylight in September / Average sunshine in September - Summit, NJ
  • Average daylight in September: 12.4h

The month with the longest days is June (Average daylight: 15.1h).
The month with the shortest days is December (Average daylight: 9.3h).

  • Average sunshine in September: 8.5h

The month with the most sunshine is July (Average sunshine: 10.3h).
The month with the least sunshine is February (Average sunshine: 4.6h).

Average sunshine days in September - Summit, NJ
  • Average sunshine days in September: 14.2 days

The month with the most sunshine days is November (18.3 days).
The month with the least sunshine days is June (10.5 days).

Average UV index in September - Summit, NJ
  • Average UV index in September: 4

Months with the highest UV index are June, July and August (UV index 6).
Months with the lowest UV index are January, February, March, November and December (UV index 2).

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

Months with the most cloud cover are February and March (Cloud cover 49).
Months with the least cloud cover are July and August (Cloud cover 34).

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

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).