September weather forecast
Somerville, MA

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Weather in September

September in Somerville Massachusetts sees the dawn of the fall season, with a noticeable drop in the highest temperature to 72.9°F (22.7°C) and the beginning of autumn colors. The winds start to pick up in frequency in comparison to the calm summer months. Evenings become cooler as the city prepares to welcome the fall season. The level of rainfall decreases to its lowest for the year, paving the way for a drier month. Sunshine hours witness a gradual decline, indicating the arrival of shorter days.

Temperature

As August shifts into September, a minor alteration in temperatures is observed, with average highs reducing from a moderately hot 80.4°F (26.9°C) to a pleasant 72.9°F (22.7°C). In the month of September, an average of 56.8°F (13.8°C) marks the low-temperature.

Humidity

In Somerville, the average relative humidity in September is 75%.

Rainfall

The month with the least rainfall is September, when the rain falls for 2.9 days and typically collects 0.12" (3mm) of precipitation.

Snowfall

In Somerville, snow does not fall in June through October.

Daylight

In Somerville, the average length of the day in September is 12h and 28min.
On the first day of the month, sunrise is at 6:10 am and sunset at 7:18 pm. On the last day of September, sunrise is at 6:41 am and sunset at 6:27 pm EDT.

Sunshine

In September, the average sunshine is 8.5h.

UV index

The average daily maximum UV index in September in Somerville is 4. A UV Index value of 3 to 5 symbolizes a medium health hazard from exposure to the Sun's UV radiation for average individuals.
Note: A daily maximum UV index of 4 in September translates into the following instructions:
Exercise prudence. Persons with fair skin could be burned in under 30 minutes. Midday Sun has the strongest UV rays, making it crucial to limit exposure and find shade. Shield yourself from the harmful effects of UV radiation with sun-protective attire, a hat, and quality sunglasses.
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Frequently asked questions

What are September temperatures in Somerville?

In Somerville, in September, the average high-temperature is 72.9°F (22.7°C), and the average low-temperature is 56.8°F (13.8°C). The average heat index (a.k.a. 'feels like', 'real feel'), which factors the actual air temperature with the relative humidity, in July is appraised at 86°F (30°C).

What is the average humidity in September in Somerville?

The average relative humidity in September is 75%.

What is the driest month in Somerville?

September is the month with the least rainfall in Somerville, Massachusetts. Rain falls for 2.9 days and accumulates 0.12" (3mm) of precipitation.

How many days does it rain in September in Somerville?

In Somerville, in September, during 2.9 rainfall days, 0.12" (3mm) of precipitation is typically accumulated.

When it does not snow in Somerville?

June through October are months without snowfall in Somerville, Massachusetts.

How many hours of daylight does Somerville have in September?

The average day length in September in Somerville, Massachusetts, is 12h and 28min.

When are sunrise and sunset in September in Somerville?

On the first day of September, sunrise is at 6:10 am and sunset at 7:18 pm. On the last day of the month, sunrise is at 6:41 am and sunset at 6:27 pm EDT.

How long on average sun shines in September in Somerville?

In September, the average sunshine duration is 8.5h.

How high is the UV index in September in Somerville?

The average daily maximum UV index in September is 4. A UV Index 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
Somerville, MA

Average temperature in September - Somerville, MA
  • Average high temperature in September: 72.9°F

The warmest month (with the highest average high temperature) is July (81.9°F).
The month with the lowest average high temperature is January (33.8°F).

  • Average low temperature in September: 56.8°F

The month with the highest average low temperature is July (64.8°F).
The coldest month (with the lowest average low temperature) is January (22.5°F).

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Average pressure in September
Somerville, MA

Average pressure in September - Somerville, MA
  • 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 (29.93"Hg).

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Average wind speed in September
Somerville, MA

Average wind speed in September - Somerville, MA
  • Average wind speed in September: 6.6mph

The windiest month (with the highest average wind speed) is January (9.6mph).
The calmest month (with the lowest average wind speed) is August (6mph).

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Average humidity in September
Somerville, MA

Average humidity in September - Somerville, MA
  • Average humidity in September: 75%

The month with the highest relative humidity is February (78%).
The month with the lowest relative humidity is April (69%).

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Average rainfall in September
Somerville, MA

Average rainfall in September - Somerville, MA
  • Average rainfall in September: 0.12"

The wettest month (with the highest rainfall) is November (0.55").
The driest month (with the least rainfall) is September (0.12").

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Average rainfall days in September
Somerville, MA

Average rainfall days in September - Somerville, MA
  • Average rainfall days in September: 2.9 days

The month with the highest number of rainy days is April (5.9 days).
The months with the least rainy days are January and September (2.9 days).

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Average snowfall in September
Somerville, MA

Average snowfall in September - Somerville, MA
  • Average snowfall in September: 0"

The month with the highest snowfall is December (0.71").
The months with the least snowfall are June, July, August, September and October (0").

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Average snowfall days in September
Somerville, MA

Average snowfall days in September - Somerville, MA
  • Average snowfall days in September: 0 days

The month with the highest number of snowfall days is January (3.4 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
Somerville, MA

Average daylight in September / Average sunshine in September - Somerville, MA
  • Average daylight in September: 12h and 3min

The month with the longest days is June (Average daylight: 15h and 12min).
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 30min).
The month with the least sunshine is February (Average sunshine: 4h and 36min).

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Average sunshine days in September
Somerville, MA

Average sunshine days in September - Somerville, MA
  • Average sunshine days in September: 24.8 days

The month with the most sunshine days is December (25.5 days).
The month with the least sunshine days is July (22.8 days).

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Average UV index in September
Somerville, MA

Average UV index in September - Somerville, MA
  • 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
Somerville, MA

Average cloud cover in September - Somerville, MA
  • Average cloud cover in September: 37

The month with the most cloud cover is March (Cloud cover 50).
The month with the least cloud cover is August (Cloud cover 32).

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Average visibility in September
Somerville, MA

Average visibility in September - Somerville, MA
  • 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).

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Somerville, Massachusetts, USA

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