September weather forecast
Washington, PA

Weather in September

September, the first month of the autumn, in Washington, is also a moderately hot month, with average temperature varying between 75.7°F (24.3°C) and 54.9°F (12.7°C).

Temperature

In September, the average high-temperature slightly decreases, from 82°F (27.8°C) in August, to a still moderately hot 75.7°F (24.3°C). In September, in Washington, the average low-temperature is 54.9°F (12.7°C).

Humidity

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

Rainfall

In Washington, during September, the rain falls for 11.7 days and regularly aggregates up to 1.02" (26mm) of precipitation. Throughout the year, there are 143 rainfall days, and 14.8" (376mm) of precipitation is accumulated.

Snowfall

June through September are months without snowfall in Washington.

Daylight

In September, the average length of the day in Washington is 12.4h.

Sunshine

In September, the average sunshine is 8.5h.

UV index

In Washington, Pennsylvania, the average daily maximum UV index in September is 4. A UV Index reading of 3 to 5 represents a medium health hazard from the exposure to the Sun's UV radiation for the ordinary person.
Note: In September, the average maximum UV index of 4 translate into the following recommendations:
Take precautions - Protection against sunburn is recommended. The solar radiation is most powerful near the mid-day, so the exposure to the direct Sun should be reduced accordingly. On bright days sunglasses that block both UVA and UVB rays should be worn. A hat with a wide brim is extremely helpful, as it can prevent roughly 50% of UV radiation from reaching the eyes.
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FAQ

What is the average humidity in September in Washington?

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

How much does it rain in Washington in September?

In Washington, during September, the rain falls for 11.7 days and regularly aggregates up to 1.02" (26mm) of precipitation.

When it does not snow in Washington?

In Washington, Pennsylvania, snow does not fall in June through September.

Does it snow in Washington in September?

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

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

In September, the average length of the day is 12.4h.

How many hours of sunshine does Washington have in September?

The average sunshine in September in Washington is 8.5h.

What is the UV index intensity in September in Washington?

The average daily maximum UV index in September in Washington is 4. A UV Index reading of 3 to 5 represents a medium health risk from unprotected exposure to the UV radiation.

Average temperature in September
Washington, PA

Average temperature in September - Washington, PA
  • Average high temperature in September: 24.3°C

The warmest month (with the highest average high temperature) is July (28.5°C).
The month with the lowest average high temperature is January (0.9°C).

  • Average low temperature in September: 12.7°C

The month with the highest average low temperature is July (16.6°C).
The coldest month (with the lowest average low temperature) is January (-6.2°C).

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Average pressure in September
Washington, PA

Average pressure in September - Washington, PA
  • Average pressure in September: 1017.6mbar

The month with the highest atmospheric pressure is November (1020.5mbar).
The month with the lowest atmospheric pressure is June (1014.2mbar).

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Average wind speed in September
Washington, PA

Average wind speed in September - Washington, PA
  • Average wind speed in September: 8.1km/h

The windiest month (with the highest average wind speed) is January (12.5km/h).
The calmest month (with the lowest average wind speed) is August (7.3km/h).

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Average humidity in September
Washington, PA

Average humidity in September - Washington, PA
  • Average humidity in September: 79%

The month with the highest relative humidity is February (85%).
The months with the lowest relative humidity are April, July and August (77%).

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Average rainfall in September
Washington, PA

Average rainfall in September - Washington, PA
  • Average rainfall in September: 26mm

The wettest month (with the highest rainfall) is July (42mm).
The driest months (with the least rainfall) are January and November (24mm).

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Average rainfall days in September
Washington, PA

Average rainfall days in September - Washington, PA
  • Average rainfall days in September: 11.7 days

The month with the highest number of rainy days is May (17.2 days).
The month with the least rainy days is February (7.3 days).

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Average snowfall in September
Washington, PA

Average snowfall in September - Washington, PA
  • Average snowfall in September: 0mm

The month with the highest snowfall is February (32mm).
The months with the least snowfall are June, July, August and September (0mm).

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Average snowfall days in September
Washington, PA

Average snowfall days in September - Washington, PA
  • Average snowfall days in September: 0 days

The month with the highest number of snowfall days is January (9.8 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
Washington, PA

Average daylight in September / Average sunshine in September - Washington, PA
  • Average daylight in September: 12.4h

The month with the longest days is June (Average daylight: 15h).
The month with the shortest days is December (Average daylight: 9.4h).

  • Average sunshine in September: 8.5h

The month with the most sunshine is August (Average sunshine: 10.2h).
The month with the least sunshine is January (Average sunshine: 3h).

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Average sunshine days in September
Washington, PA

Average sunshine days in September - Washington, PA
  • Average sunshine days in September: 15.9 days

The month with the most sunshine days is November (19.1 days).
The month with the least sunshine days is May (11.8 days).

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Average UV index in September
Washington, PA

Average UV index in September - Washington, PA
  • Average UV index in September: 4

The months with the highest UV index are June, July and August (UV index 6).
The month with the lowest UV index is December (UV index 1).

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Average cloud cover in September
Washington, PA

Average cloud cover in September - Washington, PA
  • Average cloud cover in September: 38

The month with the most cloud cover is January (Cloud cover 68).
The month with the least cloud cover is August (Cloud cover 33).

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Average visibility in September
Washington, PA

Average visibility in September - Washington, PA
  • Average visibility in September: 8km

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

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