September weather forecast
Londonderry, NH

Weather in September

The first month of the autumn, September, is still a pleasant month in Londonderry, New Hampshire, with an average temperature fluctuating between 72.1°F (22.3°C) and 54°F (12.2°C).

Temperature

In September, the average high-temperature marginally drops from a warm 80.1°F (26.7°C) in August to an agreeable 72.1°F (22.3°C). In Londonderry, the average low-temperature is 54°F (12.2°C).

Humidity

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

Rainfall

In September, in Londonderry, the rain falls for 8.4 days. Throughout September, 0.79" (20mm) of precipitation is accumulated. Throughout the year, there are 104.4 rainfall days, and 12.95" (329mm) of precipitation is accumulated.

Snowfall

June through September are months without snowfall.

Daylight

The average length of the day in September is 12h and 29min.
On the first day of September in Londonderry, sunrise is at 6:10 am and sunset at 7:20 pm. On the last day of the month, sunrise is at 6:41 am and sunset at 6:28 pm EDT.

Sunshine

In September, the average sunshine is 8.4h.

UV index

In September, the average daily maximum UV index is 4. A UV Index estimate of 3 to 5 represents a medium health hazard from exposure to the Sun's UV radiation for average individuals.
Note: In September, the average maximum UV index of 4 translate into the following recommendations:
Take precautions - Protection against sun damage is advised. The Sun's most intense and consequently most harmful UV radiation during midday hours should be decreased by minimizing exposure and seeking shade. A wide-brim hat offers excellent sun protection for the eyes, ears, face, and neck. Sunglasses with UVA and UVB protection significantly reduce eye damage from sun exposure. Tightly woven, loose-fitting clothes provide additional protection from the Sun.
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FAQ

What is the temperature in September in Londonderry?

The average high-temperature, in September, in Londonderry, New Hampshire, is 72.1°F (22.3°C), while the average low-temperature is 54°F (12.2°C). The average heat index (a.k.a. 'apparent temperature', 'felt air temperature'), which combines air temperature and relative humidity, in July is calculated to be 86°F (30°C).

What is the average humidity in September in Londonderry?

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

How much does it rain in Londonderry in September?

In September, the rain falls for 8.4 days. Throughout September, 0.79" (20mm) of precipitation is accumulated.

When it does not snow in Londonderry?

June through September are months without snowfall in Londonderry.

Does it snow in Londonderry in September?

In Londonderry, New Hampshire, in September, it doesn't snow. In October, it regularly snows.

How many hours of daylight does Londonderry have in September?

The average day length in September in Londonderry, New Hampshire, is 12h and 29min.

When are sunrise and sunset in September in Londonderry?

On the first day of September in Londonderry, sunrise is at 6:10 am and sunset at 7:20 pm. On the last day of the month, sunrise is at 6:41 am and sunset at 6:28 pm EDT.

How many hours of sunshine does Londonderry have in September?

In September, the average sunshine duration in Londonderry, New Hampshire, is 8.4h.

What is the UV index intensity in September in Londonderry?

In Londonderry, the average daily maximum UV index in September is 4. A UV Index of 3 to 5 symbolizes a moderate vulnerability from exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average snowfall
Average snowfall days
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in September
Londonderry, NH

Average temperature in September - Londonderry, NH
  • Average high temperature in September: 72.1°F

The warmest month (with the highest average high temperature) is July (81.7°F).
The month with the lowest average high temperature is January (30.6°F).

  • Average low temperature in September: 54°F

The month with the highest average low temperature is July (61°F).
The coldest month (with the lowest average low temperature) is January (18°F).

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Average pressure in September
Londonderry, NH

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

The month with the highest atmospheric pressure is November (30.07"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).

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Average wind speed in September
Londonderry, NH

Average wind speed in September - Londonderry, NH
  • Average wind speed in September: 5.5mph

The windiest month (with the highest average wind speed) is January (8.3mph).
The calmest month (with the lowest average wind speed) is August (5.1mph).

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Average humidity in September
Londonderry, NH

Average humidity in September - Londonderry, NH
  • Average humidity in September: 77%

The month with the highest relative humidity is February (81%).
The month with the lowest relative humidity is April (72%).

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Average rainfall in September
Londonderry, NH

Average rainfall in September - Londonderry, NH
  • Average rainfall in September: 0.79"

The wettest month (with the highest rainfall) is October (1.38").
The driest month (with the least rainfall) is January (0.75").

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Average rainfall days in September
Londonderry, NH

Average rainfall days in September - Londonderry, NH
  • Average rainfall days in September: 8.4 days

The month with the highest number of rainy days is June (12.1 days).
The month with the least rainy days is January (4.1 days).

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Average snowfall in September
Londonderry, NH

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

The month with the highest snowfall is December (2.99").
The months with the least snowfall are June, July, August and September (0").

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Average snowfall days in September
Londonderry, NH

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

The month with the highest number of snowfall days is January (7.1 days).
The months with the least snowfall days are June, July, August and September (0 days).

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Average daylight in September /
Average sunshine in September
Londonderry, NH

Average daylight in September / Average sunshine in September - Londonderry, NH
  • Average daylight in September: 12h and 29min

The month with the longest days is June (Average daylight: 15h and 17min).
The month with the shortest days is December (Average daylight: 9h and 5min).

  • Average sunshine in September: 8h and 24min

The month with the most sunshine is August (Average sunshine: 10h and 24min).
The month with the least sunshine is February (Average sunshine: 4h and 36min).

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Average sunshine days in September
Londonderry, NH

Average sunshine days in September - Londonderry, NH
  • Average sunshine days in September: 20 days

The months with the most sunshine days are January and December (21.3 days).
The month with the least sunshine days is June (16.7 days).

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Average UV index in September
Londonderry, NH

Average UV index in September - Londonderry, NH
  • 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).

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Average cloud cover in September
Londonderry, NH

Average cloud cover in September - Londonderry, NH
  • Average cloud cover in September: 37

The month with the most cloud cover is March (Cloud cover 51).
The month with the least cloud cover is August (Cloud cover 33).

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Average visibility in September
Londonderry, NH

Average visibility in September - Londonderry, NH
  • Average visibility in September: 5mi

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

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