September weather forecast
Williston, VT

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Weather in September

September marks the start of fall in Williston, Vermont. Witnessing a significant drop in the average high of 69.3°F (20.7°C), slight chill returns to the air, signaling the approach of winter. As leaves change color, Williston transforms into an autumnal spectacle attracting visitors from afar. The frequency of rainfall decreases, offering drier conditions as the month progresses. The wind speed experiences a modest rise, bringing with it a slight chill.

Temperature

The advent of September brings a slight shift in average high-temperature, moving from a warm 76.5°F (24.7°C) in August to an agreeable 69.3°F (20.7°C). September witnesses an average nighttime temperature of 49.1°F (9.5°C) in Williston.

Humidity

In Williston, the average relative humidity in September is 79%.

Rainfall

September is the month with the least rainfall in Williston. Rain falls for 12 days and accumulates 1.77" (45mm) of precipitation.

Snowfall

June through September are months without snowfall in Williston.

Daylight

In Williston, Vermont, the average length of the day in September is 12h and 30min.
On the first day of September in Williston, sunrise is at 6:15 am and sunset at 7:28 pm. On the last day of the month, sunrise is at 6:49 am and sunset at 6:34 pm EDT.

Sunshine

The average sunshine in September is 8.7h.

UV index

In Williston, Vermont, the average daily maximum UV index in September is 3. A UV Index of 3 to 5 symbolizes a moderate health risk from exposure to the Sun's UV radiation for ordinary individuals.
Note: During September, 3 as the daily maximum UV index converts into the following advice:
Be cautious. Those with fair skin can be subjected to burns in fewer than 30 minutes. The mid-day Sun emits the most powerful UV radiation, so seek shade and minimize exposure. Tightly woven clothing, when worn loosely, shields effectively against the Sun.
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Frequently asked questions

What is the average September temperature in Williston?

In September, in Williston, the average high-temperature is 69.3°F (20.7°C), and the average low-temperature is 49.1°F (9.5°C).

What is the average humidity in September in Williston?

In Williston, Vermont, the average relative humidity in September is 79%.

What is the driest month in Williston?

September is the month with the least rainfall in Williston, Vermont. Rain falls for 12 days and accumulates 1.77" (45mm) of precipitation.

How much does it rain in Williston in September?

In Williston, in September, it is raining for 12 days, with typically 1.77" (45mm) of accumulated precipitation.

When it does not snow in Williston?

June through September are months without snowfall in Williston, Vermont.

Does it snow in Williston in September?

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

How many hours of daylight does Williston have in September?

The average day length in September in Williston, Vermont, is 12h and 30min.

When is the sunrise / sunset in September in Williston?

In September, on the first day of the month, sunrise is at 6:15 am and sunset at 7:28 pm. On the last day of the month, in Williston, Vermont, sunrise is at 6:49 am and sunset at 6:34 pm EDT.

How long on average sun shines in September in Williston?

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

What is the UV index reading in September in Williston?

The average daily maximum UV index in September in Williston, Vermont, is 3. A UV Index estimate of 3 to 5 represents a medium hazard to health from unsafe 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
Williston, VT

Average temperature in September - Williston, VT
  • Average high temperature in September: 69.3°F

The warmest month (with the highest average high temperature) is July (78.4°F).
The month with the lowest average high temperature is January (24.3°F).

  • Average low temperature in September: 49.1°F

The month with the highest average low temperature is July (57.2°F).
The coldest month (with the lowest average low temperature) is January (12°F).

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Average pressure in September
Williston, VT

Average pressure in September - Williston, VT
  • 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 (29.91"Hg).

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Average wind speed in September
Williston, VT

Average wind speed in September - Williston, VT
  • Average wind speed in September: 5.7mph

The windiest month (with the highest average wind speed) is April (7.3mph).
The calmest month (with the lowest average wind speed) is August (5.3mph).

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Average humidity in September
Williston, VT

Average humidity in September - Williston, VT
  • Average humidity in September: 79%

The months with the highest relative humidity are January and February (87%).
The months with the lowest relative humidity are April and May (76%).

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Average rainfall in September
Williston, VT

Average rainfall in September - Williston, VT
  • Average rainfall in September: 1.77"

The wettest month (with the highest rainfall) is June (3.19").
The driest month (with the least rainfall) is September (1.77").

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Average rainfall days in September
Williston, VT

Average rainfall days in September - Williston, VT
  • Average rainfall days in September: 12 days

The month with the highest number of rainy days is June (18 days).
The month with the least rainy days is February (6.2 days).

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Average snowfall in September
Williston, VT

Average snowfall in September - Williston, VT
  • Average snowfall in September: 0"

The month with the highest snowfall is February (11.73").
The months with the least snowfall are June, July, August and September (0").

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Average snowfall days in September
Williston, VT

Average snowfall days in September - Williston, VT
  • Average snowfall days in September: 0 days

The month with the highest number of snowfall days is January (20.7 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
Williston, VT

Average daylight in September / Average sunshine in September - Williston, VT
  • Average daylight in September: 12h and 3min

The month with the longest days is June (Average daylight: 15h and 30min).
The month with the shortest days is December (Average daylight: 8h and 54min).

  • Average sunshine in September: 8h and 4min

The month with the most sunshine is July (Average sunshine: 10h and 12min).
The month with the least sunshine is February (Average sunshine: 2h and 48min).

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Average sunshine days in September
Williston, VT

Average sunshine days in September - Williston, VT
  • Average sunshine days in September: 15.9 days

The month with the most sunshine days is September (15.9 days).
The month with the least sunshine days is February (6.8 days).

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Average UV index in September
Williston, VT

Average UV index in September - Williston, VT
  • Average UV index in September: 3

The months with the highest UV index are May, June, July and August (UV index 5).
The months with the lowest UV index are January and December (UV index 1).

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Average cloud cover in September
Williston, VT

Average cloud cover in September - Williston, VT
  • Average cloud cover in September: 37

The month with the most cloud cover is February (Cloud cover 72).
The month with the least cloud cover is July (Cloud cover 35).

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Average visibility in September
Williston, VT

Average visibility in September - Williston, VT
  • Average visibility in September: 5mi

The months with the highest visibility are April, May, June, July, August, September, October, November and December (5mi).
The months with the lowest visibility are January, February and March (4mi).

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Williston, Vermont, USA

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