September weather forecast
Newtown, CT

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Weather in September

With the arrival of September, Newtown, Connecticut starts to reflect the stunning changes of autumn. Despite this, the temperature still hovers in the mild range with a peak of 73°F (22.8°C). As the city shifts from summer to fall, daylight hours reduce further, casting longer shadows that add to Newtown's autumn charm. The cityscape begins to transform, adopting earthy hues from the changing foliage. September ushers in cooler winds, shorter days, and scenic beauty indicative of the imminent fall season.

Temperature

The average high-temperature shows a slight dip in September, from August's moderately hot 80.2°F (26.8°C) to a pleasant 73°F (22.8°C). An average minimum temperature of 57°F (13.9°C) marks the month of September.

Humidity

The average relative humidity in September is 77%.

Rainfall

January and September are months with the least rain in Newtown when the rain falls for 13.4 days and typically aggregates up to 2.4" (61mm) of rain.

Snowfall

June through September are months without snowfall in Newtown.

Daylight

In Newtown, the average length of the day in September is 12h and 28min.
On the first day of the month, sunrise is at 6:20 am and sunset at 7:25 pm. On the last day of September, in Newtown, Connecticut, sunrise is at 6:49 am and sunset at 6:36 pm EDT.

Sunshine

In September, the average sunshine is 8.7h.

UV index

The average daily maximum UV index in September is 4. A UV Index of 3 to 5 symbolizes a moderate threat to health from exposure to the Sun's UV radiation for ordinary individuals.
Note: The UV index of 4 during September leads to these advisories:
Make use of precautions - It is urged to ward off sun damage. The mid-day Sun emits the most powerful UV radiation, so seek shade and minimize exposure. Opt for tightly woven and loose clothing to enhance protection from the Sun.
Updated: Feb 10, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What are the temperatures in Newtown in September?

The average high-temperature, in September, in Newtown, is 73°F (22.8°C), while the average low-temperature is 57°F (13.9°C). In July, the average heat index (a.k.a. 'apparent temperature', 'feels like'), which factors the actual air temperature with the relative humidity, is computed to be 87.8°F (31°C).

What is the average humidity in September in Newtown?

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

What is the driest month in Newtown?

The months with the least rainfall in Newtown are January and September Rain falls for 13.4 days and accumulates 2.4" (61mm) of rain.

How many days does it rain in September in Newtown?

In Newtown, in September, it is raining for 13.4 days, with typically 2.4" (61mm) of accumulated precipitation.

When it does not snow in Newtown?

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

Does it snow in Newtown in September?

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

What is the average length of the day in September in Newtown?

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

What time are sunrise and sunset in September in Newtown?

On the first day of September in Newtown, Connecticut, sunrise is at 6:20 am and sunset at 7:25 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 Newtown have in September?

The average sunshine duration in September is 8.7h.

How high is the UV index in September in Newtown?

In September, the average daily maximum UV index is 4. A UV Index value of 3 to 5 symbolizes a moderate health threat from exposure to the Sun's 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
Newtown, CT

Average temperature in September - Newtown, CT
  • Average high temperature in September: 73°F

The warmest month (with the highest average high temperature) is July (82.2°F).
The month with the lowest average high temperature is January (33.4°F).

  • Average low temperature in September: 57°F

The month with the highest average low temperature is July (64.9°F).
The coldest month (with the lowest average low temperature) is January (22.6°F).

Average pressure in September
Newtown, CT

Average pressure in September - Newtown, 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).

Average wind speed in September
Newtown, CT

Average wind speed in September - Newtown, CT
  • Average wind speed in September: 6.1mph

The windiest month (with the highest average wind speed) is January (8.5mph).
The calmest month (with the lowest average wind speed) is August (5.3mph).

Average humidity in September
Newtown, CT

Average humidity in September - Newtown, CT
  • Average humidity in September: 77%

The month with the highest relative humidity is February (79%).
The month with the lowest relative humidity is April (72%).

Average rainfall in September
Newtown, CT

Average rainfall in September - Newtown, CT
  • Average rainfall in September: 2.4"

The wettest month (with the highest rainfall) is December (4.02").
The driest months (with the least rainfall) are January and September (2.4").

Average rainfall days in September
Newtown, CT

Average rainfall days in September - Newtown, CT
  • Average rainfall days in September: 13.4 days

The month with the highest number of rainy days is July (18.6 days).
The month with the least rainy days is January (9.1 days).

Average snowfall in September
Newtown, CT

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

The month with the highest snowfall is February (4.37").
The months with the least snowfall are June, July, August and September (0").

Average snowfall days in September
Newtown, CT

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

The month with the highest number of snowfall days is February (9.5 days).
The months with the least snowfall days are June, July, August and September (0 days).

Average daylight in September /
Average sunshine in September
Newtown, CT

Average daylight in September / Average sunshine in September - Newtown, CT
  • Average daylight in September: 12h and 3min

The month with the longest days is June (Average daylight: 15h and 6min).
The month with the shortest days is December (Average daylight: 9h and 12min).

  • Average sunshine in September: 8h and 4min

The months with the most sunshine are July and August (Average sunshine: 10h and 18min).
The month with the least sunshine is February (Average sunshine: 4h and 36min).

Average sunshine days in September
Newtown, CT

Average sunshine days in September - Newtown, CT
  • Average sunshine days in September: 13.9 days

The month with the most sunshine days is November (17.2 days).
The month with the least sunshine days is June (10.1 days).

Average UV index in September
Newtown, CT

Average UV index in September - Newtown, CT
  • 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).

Average cloud cover in September
Newtown, CT

Average cloud cover in September - Newtown, CT
  • Average cloud cover in September: 36

The months with the most cloud cover are February, March and December (Cloud cover 49).
The month with the least cloud cover is August (Cloud cover 32).

Average visibility in September
Newtown, CT

Average visibility in September - Newtown, CT
  • Average visibility in September: 6mi

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

Newtown, Connecticut, USA

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