September weather forecast and climate
Williston, NY

September, the first month of the autumn, in Williston, is also an agreeable month, with average temperature varying between 53.6°F (12°C) and 71.6°F (22°C).

Temperature

In September, the average high-temperature slightly decreases, from a moderately hot 77.5°F (25.3°C) in August, to an agreeable 71.6°F (22°C). The average low-temperature, in September, is 53.6°F (12°C).

Humidity

In Williston, the average relative humidity is 78%.

Rainfall

The month with the least rainfall in Williston is September when the rain falls for 14.3 days and typically collects 1.34" (34mm) of precipitation.

Snowfall

June through September are months without snowfall in Williston.

Daylight

In Williston, the average length of the day in September is 12.5h.

Sunshine

In September, the average sunshine is 8.8h.

UV index

In Williston, the average daily maximum UV index is 3. A UV Index estimate of 3 to 5 represents a medium vulnerability from the exposure to the Sun's UV rays for the ordinary person.
Note: The daily maximum UV index of 3 interpret into the following advice:
Take precautions - Protection against sun damage is advised. The Sun's most intense and consequently most harmful UV radiation during midday hours should be decreased by minimizing exposure and seeking shade. A wide-brim hat offers excellent sun protection for eyes, ears, face, and neck. Sunglasses with UVA and UVB protection significantly reduce eye damage from sun exposure. Tightly woven, loose-fitting clothes provide additional protection from the Sun.

What is the temperature in September in Williston?

The average high-temperature, in September, in Williston, is 71.6°F (22°C), while the average low-temperature is 53.6°F (12°C).

What is the average humidity in September in Williston?

The average relative humidity in September is 78%.

How much does it rain in Williston in September?

In Williston, in September, it is raining for 14.3 days, with typically 1.34" (34mm) of accumulated precipitation.

What is the driest month in Williston?

The month with the least rainfall in Williston, New York, is September when the rain falls for 14.3 days and typically collects 1.34" (34mm) of precipitation.

Does it snow in Williston in September?

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

When it does not snow in Williston?

June through September are months without snowfall in Williston, New York.

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

The average length of the day in September in Williston is 12.5h.

How long on average sun shines in September in Williston?

In Williston, the average sunshine in September is 8.8h.

What is the UV index reading in September in Williston?

The average daily maximum UV index in September is 3. A UV Index reading of 3 to 5 represents a medium hazard to health from the exposure to the Sun's UV rays.
Average temperature in September - Williston, NY
  • Average high temperature in September: 22°C

The warmest month (with the highest average high temperature) is July (26.2°C).
The month with the lowest average high temperature is January (-1.7°C).

  • Average low temperature in September: 12°C

The month with the highest average low temperature is July (16.1°C).
The coldest month (with the lowest average low temperature) is January (-7.7°C).

Average pressure in September - Williston, NY
  • Average pressure in September: 1017.5mbar

The month with the highest atmospheric pressure is November (1018.9mbar).
The month with the lowest atmospheric pressure is June (1013.4mbar).

Average wind speed in September - Williston, NY
  • Average wind speed in September: 10.7km/h

The windiest month (with the highest average wind speed) is January (16.6km/h).
The calmest month (with the lowest average wind speed) is July (10.3km/h).

Average humidity in September - Williston, NY
  • Average humidity in September: 78%

Months with the highest relative humidity are January and February (87%).
Months with the lowest relative humidity are May, July and August (77%).

Average rainfall in September - Williston, NY
  • Average rainfall in September: 34mm

The wettest month (with the highest rainfall) is May (62mm).
The driest month (with the least rainfall) is September (34mm).

Average rainfall days in September - Williston, NY
  • Average rainfall days in September: 14.3 days

The month with the highest number of rainy days is July (18 days).
The month with the least rainy days is February (6.8 days).

Average snowfall in September - Williston, NY
  • Average snowfall in September: 0mm

The month with the highest snowfall is February (168mm).
Months with the least snowfall are June, July, August and September (0mm).

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

The month with the highest number of snowfall days is January (19 days).
Months with the least snowfall days are June, July, August and September (0 days).

Average daylight in September / Average sunshine in September - Williston, NY
  • Average daylight in September: 12.5h

The month with the longest days is June (Average daylight: 15.3h).
The month with the shortest days is December (Average daylight: 9.1h).

  • Average sunshine in September: 8.8h

The month with the most sunshine is July (Average sunshine: 10.3h).
The month with the least sunshine is January (Average sunshine: 2.3h).

Average sunshine days in September - Williston, NY
  • Average sunshine days in September: 12.5 days

The month with the most sunshine days is June (13.4 days).
The month with the least sunshine days is February (6.7 days).

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

The month with the highest UV index is July (UV index 6).
Months with the lowest UV index are January and December (UV index 1).

Average cloud cover in September - Williston, NY
  • Average cloud cover in September: 36

The month with the most cloud cover is January (Cloud cover 78).
The month with the least cloud cover is August (Cloud cover 32).

Average visibility in September - Williston, NY
  • Average visibility in September: 9km

Months with the highest visibility are April, May, June, July, August, September, October and November (9km).
Months with the lowest visibility are January, February, March and December (8km).