September weather forecast
Williamstown, KY

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Weather in September

September, the first month of the autumn in Williamstown, is still a warm month, with an average temperature varying between 58.5°F (14.7°C) and 78.3°F (25.7°C).

Temperature

Williamstown's progression into September involves a minor drop in the average high-temperature, slightly receding from a moderately hot 84.6°F (29.2°C) in August to a still warm 78.3°F (25.7°C). During September, Williamstown experiences an average low-temperature of 58.5°F (14.7°C) at night.

Humidity

The average relative humidity in September is 75%.

Rainfall

The month with the least rainfall is September, when the rain falls for 13.9 days and typically collects 2.13" (54mm) of precipitation.

Snowfall

In Williamstown, snow does not fall in May through September.

Daylight

The average length of the day in September is 12h and 25min.
On the first day of the month, sunrise is at 7:08 am and sunset at 8:07 pm. On the last day of September, sunrise is at 7:33 am and sunset at 7:22 pm EDT.

Sunshine

In Williamstown, the average sunshine in September is 8.2h.

UV index

In September, the average daily maximum UV index is 5. A UV Index estimate of 3 to 5 represents a medium health hazard from exposure to the Sun's UV rays for the ordinary person.
Note: In September, the maximum UV index of 5 suggests this advice:
Put precautions into practice - Protective measures against sun-induced damage are advised. Avoiding direct sun during mid-day hours can prevent harmful UV radiation exposure. A wide-brimmed hat is a shield, deflecting up to 50% of harmful UV radiation from eyes.

Frequently asked questions

What are September temperatures?

Williamstown in September has an average high-temperature of 78.3°F (25.7°C) and an average low-temperature of 58.5°F (14.7°C). The average heat index (a.k.a. 'felt air temperature', 'apparent temperature'), which factors the actual air temperature with the relative humidity, in August is estimated at 93.2°F (34°C).

What is the average humidity in September?

In Williamstown, the average relative humidity in September is 75%.

What is the driest month in Williamstown?

September is the month with the least rainfall. Rain falls for 13.9 days and accumulates 2.13" (54mm) of precipitation.

How much does it rain in September?

In Williamstown, in September, during 13.9 rainfall days, 2.13" (54mm) of precipitation is typically accumulated.

When it does not snow?

In Williamstown, snow does not fall in May through September.

Does it snow in September?

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

How many hours of daylight does Williamstown have in September?

In September, the average day length is 12h and 25min.

What time are sunrise and sunset in September?

In September, on the first day of the month, sunrise is at 7:08 am and sunset at 8:07 pm. On the last day of the month, sunrise is at 7:33 am and sunset at 7:22 pm EDT.

How long on average sun shines in September?

In September, the average sunshine duration is 8.2h.

What is the UV index intensity in September?

In September, the average daily maximum UV index is 5. A UV Index value of 3 to 5 symbolizes 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
Williamstown, KY

Average temperature in September - Williamstown, KY
  • Average high temperature in September: 78.3°F

The warmest month (with the highest average high temperature) is July (85.3°F).
The month with the lowest average high temperature is January (37°F).

  • Average low temperature in September: 58.5°F

The month with the highest average low temperature is July (66°F).
The coldest month (with the lowest average low temperature) is January (24.6°F).

Average pressure in September
Williamstown, KY

Average pressure in September - Williamstown, KY
  • Average pressure in September: 30.03"Hg

The months with the highest atmospheric pressure are January and November (30.15"Hg).
The month with the lowest atmospheric pressure is June (29.95"Hg).

Average wind speed in September
Williamstown, KY

Average wind speed in September - Williamstown, KY
  • Average wind speed in September: 5.5mph

The windiest month (with the highest average wind speed) is January (8.6mph).
The calmest months (with the lowest average wind speed) are July and August (5mph).

Average humidity in September
Williamstown, KY

Average humidity in September - Williamstown, KY
  • Average humidity in September: 75%

The months with the highest relative humidity are February and December (81%).
The month with the lowest relative humidity is August (74%).

Average rainfall in September
Williamstown, KY

Average rainfall in September - Williamstown, KY
  • Average rainfall in September: 2.13"

The wettest month (with the highest rainfall) is April (3.82").
The driest month (with the least rainfall) is September (2.13").

Average rainfall days in September
Williamstown, KY

Average rainfall days in September - Williamstown, KY
  • Average rainfall days in September: 13.9 days

The month with the highest number of rainy days is May (18.8 days).
The month with the least rainy days is November (10.6 days).

Average snowfall in September
Williamstown, KY

Average snowfall in September - Williamstown, KY
  • Average snowfall in September: 0"

The month with the highest snowfall is February (3.35").
The months with the least snowfall are May, June, July, August and September (0").

Average snowfall days in September
Williamstown, KY

Average snowfall days in September - Williamstown, KY
  • Average snowfall days in September: 0 days

The month with the highest number of snowfall days is January (10.3 days).
The months with the least snowfall days are May, June, July, August and September (0 days).

Average daylight in September /
Average sunshine in September
Williamstown, KY

Average daylight in September / Average sunshine in September - Williamstown, KY
  • Average daylight in September: 12h and 2min

The month with the longest days is June (Average daylight: 14h and 48min).
The month with the shortest days is December (Average daylight: 9h and 30min).

  • Average sunshine in September: 8h and 1min

The months with the most sunshine are June and July (Average sunshine: 10h and 6min).
The month with the least sunshine is January (Average sunshine: 4h and 0min).

Average sunshine days in September
Williamstown, KY

Average sunshine days in September - Williamstown, KY
  • Average sunshine days in September: 14.4 days

The month with the most sunshine days is October (17 days).
The month with the least sunshine days is February (10.5 days).

Average UV index in September
Williamstown, KY

Average UV index in September - Williamstown, KY
  • Average UV index in September: 5

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, November and December (UV index 2).

Average cloud cover in September
Williamstown, KY

Average cloud cover in September - Williamstown, KY
  • Average cloud cover in September: 33

The month with the most cloud cover is January (Cloud cover 59).
The month with the least cloud cover is August (Cloud cover 29).

Average visibility in September
Williamstown, KY

Average visibility in September - Williamstown, KY
  • Average visibility in September: 6mi

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

Williamstown, Kentucky, USA

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