September weather forecast
Durham, NH

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Weather in September

September ushers in the early signs of fall in Durham. Compared to August, the temperatures in September show a decline but remain comfortably warm. The month of September marks a substantial decrease in rainfall, measuring at 1.46" (37mm). As fall approaches, the days shorten and temperatures drop, preparing Durham for the oncoming cooler months. Regardless, lingering warmth from the summer offers an opportunity to enjoy the stunning fall foliage.

Temperature

September ushers in a minor alteration in Durham's climate, with the average high-temperature moving from August's warm 76.8°F (24.9°C) to a pleasant 69.6°F (20.9°C). Durham reports an average nighttime low-temperature of 55°F (12.8°C) in September.

Humidity

In September, the average relative humidity is 79%.

Rainfall

The month with the least rainfall in Durham is September, when the rain falls for 11.4 days and typically collects 1.46" (37mm) of precipitation.

Snowfall

May through September are months without snowfall.

Daylight

In September, the average length of the day is 12h and 29min.
On the first day of September, sunrise is at 6:08 am and sunset at 7:18 pm. On the last day of the month, sunrise is at 6:40 am and sunset at 6:26 pm EDT.

Sunshine

In Durham, 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 medium health hazard from exposure to the Sun's UV radiation for the average person.
Note: A maximum daily UV index of 4 during September morphs into the following directions:
Take heed. Individuals of lighter complexion can be burned in less than half an hour. It's crucial to reduce time in the direct Sun around mid-day due to the intense solar radiation. Employ a hat with a wide brim for robust protection, cutting UV exposure by half.
Updated: Jun 22, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the temperature in September?

The high-temperature, in September, in Durham, records 69.6°F (20.9°C), while the low-temperature is 55°F (12.8°C).

What is the average humidity in September?

In Durham, the average relative humidity in September is 79%.

What is the driest month?

The month with the least rainfall is September, when the rain falls for 11.4 days and typically collects 1.46" (37mm) of precipitation.

How many days does it rain in September?

In September, in Durham, the rain falls for 11.4 days. Throughout September, 1.46" (37mm) of precipitation is accumulated.

When it does not snow?

May through September are months without snowfall.

Does it snow in September?

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

What is the average length of the day in September?

In September, the average day length is 12h and 29min.

When are sunrise and sunset in September?

On the first day of September, sunrise is at 6:08 am and sunset at 7:18 pm. On the last day of the month, sunrise is at 6:40 am and sunset at 6:26 pm EDT.

How long on average sun shines in September?

The average sunshine duration in September is 8.5h.

How high is the UV index in September in Durham?

In September, the average daily maximum UV index 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
Durham, NH

Average temperature in September - Durham, NH
  • Average high temperature in September: 69.6°F

The warmest month (with the highest average high temperature) is July (77.4°F).
The month with the lowest average high temperature is January (31.5°F).

  • Average low temperature in September: 55°F

The month with the highest average low temperature is July (61.5°F).
The coldest month (with the lowest average low temperature) is January (19.8°F).

Average pressure in September
Durham, NH

Average pressure in September - Durham, NH
  • Average pressure in September: 30.05"Hg

The month with the highest atmospheric pressure is November (30.06"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).

Average wind speed in September
Durham, NH

Average wind speed in September - Durham, NH
  • Average wind speed in September: 7mph

The windiest month (with the highest average wind speed) is January (10.8mph).
The calmest months (with the lowest average wind speed) are July and August (6.2mph).

Average humidity in September
Durham, NH

Average humidity in September - Durham, NH
  • Average humidity in September: 79%

The months with the highest relative humidity are January and February (80%).
The months with the lowest relative humidity are April and November (75%).

Average rainfall in September
Durham, NH

Average rainfall in September - Durham, NH
  • Average rainfall in September: 1.46"

The wettest months (with the highest rainfall) are October and December (2.87").
The driest month (with the least rainfall) is September (1.46").

Average rainfall days in September
Durham, NH

Average rainfall days in September - Durham, NH
  • Average rainfall days in September: 11.4 days

The month with the highest number of rainy days is May (15 days).
The month with the least rainy days is February (7.6 days).

Average snowfall in September
Durham, NH

Average snowfall in September - Durham, NH
  • Average snowfall in September: 0"

The month with the highest snowfall is December (4.53").
The months with the least snowfall are May, June, July, August and September (0").

Average snowfall days in September
Durham, NH

Average snowfall days in September - Durham, NH
  • Average snowfall days in September: 0 days

The month with the highest number of snowfall days is January (8.7 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
Durham, NH

Average daylight in September / Average sunshine in September - Durham, NH
  • Average daylight in September: 12h and 3min

The month with the longest days is June (Average daylight: 15h and 18min).
The month with the shortest days is December (Average daylight: 9h and 6min).

  • Average sunshine in September: 8h and 3min

The month with the most sunshine is August (Average sunshine: 10h and 36min).
The months with the least sunshine are February and December (Average sunshine: 4h and 48min).

Average sunshine days in September
Durham, NH

Average sunshine days in September - Durham, NH
  • Average sunshine days in September: 16.5 days

The month with the most sunshine days is November (17.1 days).
The month with the least sunshine days is April (13.2 days).

Average UV index in September
Durham, NH

Average UV index in September - Durham, NH
  • Average UV index in September: 4

The months with the highest UV index are 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
Durham, NH

Average cloud cover in September - Durham, NH
  • Average cloud cover in September: 33

The month with the most cloud cover is March (Cloud cover 50).
The month with the least cloud cover is August (Cloud cover 30).

Average visibility in September
Durham, NH

Average visibility in September - Durham, NH
  • 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).

Durham, New Hampshire, USA

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