September weather forecast
South Yarmouth, MA

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Weather in September

The first month of the autumn, September, is still a refreshing month in South Yarmouth, Massachusetts, with temperature in the range of an average low of 63°F (17.2°C) and an average high of 67.1°F (19.5°C).

Temperature

The introduction of September notes a subtle temperature variation to an enjoyable 67.1°F (19.5°C) from August's 72.1°F (22.3°C). Throughout September, South Yarmouth observes a steady low-temperature average of 63°F (17.2°C), reflecting a minor dip from daytime highs.

Humidity

The average relative humidity in September is 79%.

Rainfall

In South Yarmouth, during September, the rain falls for 9.5 days and regularly aggregates up to 1.18" (30mm) of precipitation. Throughout the year, in South Yarmouth, there are 129 rainfall days, and 14.21" (361mm) of precipitation is accumulated.

Snowfall

May through November are months without snowfall in South Yarmouth.

Ocean temperature

In September, the average ocean temperature is 64.2°F (17.9°C).
Note: Most people find swimming in 64.2°F (17.9°C) to be not enjoyable. The control of one's breathing becomes more challenging as the water temperature drops below 69.8°F (21°C).

Daylight

In September, the average length of the day is 12h and 28min.
On the first day of September, sunrise is at 6:07 am and sunset at 7:13 pm. On the last day of the month, sunrise is at 6:37 am and sunset at 6:23 pm EDT.

Sunshine

In September, the average sunshine in South Yarmouth is 8.7h.

UV index

The average daily maximum UV index in September in South Yarmouth is 4. A UV Index of 3 to 5 symbolizes a medium health hazard from unsafe exposure to UV radiation for the average person.
Note: In September, the maximum UV index of 4 translates into these guidelines:
Heed the precautions - Protecting the skin and eyes from damage is compulsory. The Sun is at its harshest during midday; protect yourself by staying in shaded areas and minimizing exposure. Enhance your sun protection with tightly woven, yet airy clothing.
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Frequently asked questions

What are September temperatures in South Yarmouth?

The average high-temperature, in September, in South Yarmouth, is 67.1°F (19.5°C), while the average low-temperature is 63°F (17.2°C).

What is the average humidity in September in South Yarmouth?

In September, the average relative humidity in South Yarmouth, Massachusetts, is 79%.

How much does it rain in South Yarmouth in September?

In September, the rain falls for 9.5 days. Throughout September, 1.18" (30mm) of precipitation is accumulated.

When it does not snow in South Yarmouth?

May through November are months without snowfall in South Yarmouth.

What is the ocean temperature in September in South Yarmouth?

In September, the average ocean temperature in South Yarmouth is 64.2°F (17.9°C). For most, swimming in 64.2°F (17.9°C) is not an enjoyable activity. Furthermore, controlling your breathing becomes progressively more difficult as the water temperature decreases from 69.8°F (21°C) to 59°F (15°C).

What is the average length of the day in September in South Yarmouth?

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

When are sunrise and sunset in September in South Yarmouth?

On the first day of September, sunrise is at 6:07 am and sunset at 7:13 pm. On the last day of the month, sunrise is at 6:37 am and sunset at 6:23 pm EDT.

How long on average sun shines in September in South Yarmouth?

In South Yarmouth, the average sunshine duration in September is 8.7h.

How high is the UV index in September in South Yarmouth?

In South Yarmouth, the average daily maximum UV index in September is 4. A UV Index reading of 3 to 5 represents a medium health risk 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
South Yarmouth, MA

Average temperature in September - South Yarmouth, MA
  • Average high temperature in September: 67.1°F

The warmest month (with the highest average high temperature) is August (72.1°F).
The month with the lowest average high temperature is January (38.5°F).

  • Average low temperature in September: 63°F

The month with the highest average low temperature is August (68.5°F).
The coldest month (with the lowest average low temperature) is January (30.6°F).

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Average pressure in September
South Yarmouth, MA

Average pressure in September - South Yarmouth, 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
South Yarmouth, MA

Average wind speed in September - South Yarmouth, MA
  • Average wind speed in September: 12.8mph

The windiest month (with the highest average wind speed) is January (16.8mph).
The calmest months (with the lowest average wind speed) are July and August (10.9mph).

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Average humidity in September
South Yarmouth, MA

Average humidity in September - South Yarmouth, MA
  • Average humidity in September: 79%

The months with the highest relative humidity are June and July (84%).
The month with the lowest relative humidity is November (74%).

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Average rainfall in September
South Yarmouth, MA

Average rainfall in September - South Yarmouth, MA
  • Average rainfall in September: 1.18"

The wettest month (with the highest rainfall) is October (1.93").
The driest month (with the least rainfall) is August (0.94").

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Average rainfall days in September
South Yarmouth, MA

Average rainfall days in September - South Yarmouth, MA
  • Average rainfall days in September: 9.5 days

The month with the highest number of rainy days is May (12.5 days).
The month with the least rainy days is February (8.3 days).

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Average snowfall in September
South Yarmouth, MA

Average snowfall in September - South Yarmouth, MA
  • Average snowfall in September: 0"

The month with the highest snowfall is January (0.87").
The months with the least snowfall are May, June, July, August, September, October and November (0").

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Average snowfall days in September
South Yarmouth, MA

Average snowfall days in September - South Yarmouth, MA
  • Average snowfall days in September: 0 days

The month with the highest number of snowfall days is January (6.4 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).

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Average sea temperature in September
South Yarmouth, MA

Average sea temperature in September - South Yarmouth, MA
  • Average sea temperature in September: 64.3°F

The best month for swimming (with the highest average sea temperature) is August (67.5°F).
The coldest month (with the lowest average sea temperature) is March (39°F).

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Average daylight in September /
Average sunshine in September
South Yarmouth, MA

Average daylight in September / Average sunshine in September - South Yarmouth, 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 12min).

  • Average sunshine in September: 8h and 4min

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

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Average sunshine days in September
South Yarmouth, MA

Average sunshine days in September - South Yarmouth, MA
  • Average sunshine days in September: 18.6 days

The month with the most sunshine days is September (18.6 days).
The month with the least sunshine days is February (14.3 days).

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Average UV index in September
South Yarmouth, MA

Average UV index in September - South Yarmouth, MA
  • 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).

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Average cloud cover in September
South Yarmouth, MA

Average cloud cover in September - South Yarmouth, MA
  • Average cloud cover in September: 31

The month with the most cloud cover is December (Cloud cover 51).
The month with the least cloud cover is August (Cloud cover 27).

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Average visibility in September
South Yarmouth, MA

Average visibility in September - South Yarmouth, 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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South Yarmouth, Massachusetts, USA

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