September weather forecast
Cornwall, CT

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Weather in September

September, the first month of the autumn in Cornwall, is also an agreeable month, with an average temperature fluctuating between 53.4°F (11.9°C) and 72°F (22.2°C).

Temperature

With the onset of September, the average high-temperature subtly recedes from August's moderately hot 79.2°F (26.2°C) to an agreeable 72°F (22.2°C). Throughout September, Cornwall records an average temperature of 53.4°F (11.9°C) at night.

Humidity

In September, the average relative humidity is 80%.

Rainfall

In Cornwall, in September, during 13.5 rainfall days, 2.24" (57mm) of precipitation is typically accumulated. In Cornwall, Connecticut, during the entire year, the rain falls for 160.5 days and collects up to 33.86" (860mm) of precipitation.

Snowfall

In Cornwall, Connecticut, snow does not fall in June through September.

Daylight

In September, the average length of the day is 12h and 28min.
On the first day of the month, sunrise is at 6:19 am and sunset at 7:26 pm. On the last day of September, in Cornwall, Connecticut, sunrise is at 6:49 am and sunset at 6:36 pm EDT.

Sunshine

The average sunshine in September in Cornwall is 8.5h.

UV index

In Cornwall, the average daily maximum UV index in September is 4. A UV Index reading of 3 to 5 represents a moderate threat to health from unsafe exposure to UV radiation for ordinary individuals.
Note: A daily maximum UV index of 4 in September translates into the following instructions:
Take necessary precautions - Suggestions to elude sunburn are provided. Considering the strength of solar radiation at midday, one should avoid direct Sun exposure. For minimizing sun-related eye damage, always choose sunglasses with UVA and UVB coverage.
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Frequently asked questions

What are the temperatures in Cornwall in September?

An average high-temperature, in September, in Cornwall, is 72°F (22.2°C) and the average low-temperature is 53.4°F (11.9°C). In July, the average heat index (a.k.a. 'real feel', 'feels like'), which takes the relative humidity and factors it into the air temperature reading, is appraised at 86°F (30°C).

What is the average humidity in September in Cornwall?

In September, the average relative humidity is 80%.

How much does it rain in Cornwall in September?

In September, in Cornwall, the rain falls for 13.5 days. Throughout September, 2.24" (57mm) of precipitation is accumulated.

When it does not snow in Cornwall?

June through September are months without snowfall in Cornwall.

Does it snow in Cornwall in September?

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

How many hours of daylight does Cornwall have in September?

The average day length in September in Cornwall is 12h and 28min.

When are sunrise and sunset in September in Cornwall?

In September, on the first day of the month, sunrise is at 6:19 am and sunset at 7:26 pm. On the last day of the month, sunrise is at 6:49 am and sunset at 6:36 pm EDT.

How many hours of sunshine does Cornwall have in September?

In Cornwall, the average sunshine duration in September is 8.5h.

What is the UV index reading in September in Cornwall?

In September, the average daily maximum UV index is 4. A UV Index reading of 3 to 5 represents a medium health risk from exposure to Sun's UV rays.
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
Cornwall, CT

Average temperature in September - Cornwall, CT
  • Average high temperature in September: 72°F

The warmest month (with the highest average high temperature) is July (81.1°F).
The month with the lowest average high temperature is January (30.9°F).

  • Average low temperature in September: 53.4°F

The month with the highest average low temperature is July (61.3°F).
The coldest month (with the lowest average low temperature) is January (18.9°F).

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Average pressure in September
Cornwall, CT

Average pressure in September - Cornwall, CT
  • Average pressure in September: 30.06"Hg

The month with the highest atmospheric pressure is November (30.09"Hg).
The month with the lowest atmospheric pressure is June (29.93"Hg).

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Average wind speed in September
Cornwall, CT

Average wind speed in September - Cornwall, CT
  • Average wind speed in September: 5.5mph

The windiest months (with the highest average wind speed) are January and March (8mph).
The calmest months (with the lowest average wind speed) are July and August (5mph).

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Average humidity in September
Cornwall, CT

Average humidity in September - Cornwall, CT
  • Average humidity in September: 80%

The month with the highest relative humidity is February (82%).
The month with the lowest relative humidity is April (74%).

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Average rainfall in September
Cornwall, CT

Average rainfall in September - Cornwall, CT
  • Average rainfall in September: 2.24"

The wettest month (with the highest rainfall) is July (3.54").
The driest month (with the least rainfall) is January (2.17").

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Average rainfall days in September
Cornwall, CT

Average rainfall days in September - Cornwall, CT
  • Average rainfall days in September: 13.5 days

The month with the highest number of rainy days is July (17.9 days).
The month with the least rainy days is January (7.7 days).

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Average snowfall in September
Cornwall, CT

Average snowfall in September - Cornwall, CT
  • Average snowfall in September: 0"

The month with the highest snowfall is February (5.16").
The months with the least snowfall are June, July, August and September (0").

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Average snowfall days in September
Cornwall, CT

Average snowfall days in September - Cornwall, CT
  • Average snowfall days in September: 0 days

The month with the highest number of snowfall days is February (10.3 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
Cornwall, CT

Average daylight in September / Average sunshine in September - Cornwall, CT
  • 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 3min

The month with the most sunshine is July (Average sunshine: 10h and 6min).
The month with the least sunshine is February (Average sunshine: 4h and 12min).

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Average sunshine days in September
Cornwall, CT

Average sunshine days in September - Cornwall, CT
  • Average sunshine days in September: 14.7 days

The month with the most sunshine days is January (16.8 days).
The month with the least sunshine days is June (10.8 days).

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Average UV index in September
Cornwall, CT

Average UV index in September - Cornwall, CT
  • Average UV index in September: 4

The month with the highest UV index is June (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
Cornwall, CT

Average cloud cover in September - Cornwall, CT
  • Average cloud cover in September: 40

The month with the most cloud cover is February (Cloud cover 53).
The months with the least cloud cover are July and August (Cloud cover 37).

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Average visibility in September
Cornwall, CT

Average visibility in September - Cornwall, CT
  • Average visibility in September: 5mi

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

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Cornwall, Connecticut, USA

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