September weather forecast
Greenacres, WA

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Weather in September

The first month of the autumn, September, is still a pleasant month in Greenacres, Washington, with an average temperature fluctuating between 72.5°F (22.5°C) and 48.2°F (9°C).

Temperature

September comes with a decrease in the average high-temperature, falling from a moderately hot 83.3°F (28.5°C) in August to an agreeable 72.5°F (22.5°C). A pronounced dip becomes evident during the nights in September as Greenacres logs a consistent average temperature of 48.2°F (9°C).

Humidity

In September, the average relative humidity is 52%.

Rainfall

In Greenacres, during September, the rain falls for 7.9 days and regularly aggregates up to 0.63" (16mm) of precipitation. In Greenacres, during the entire year, the rain falls for 125.4 days and collects up to 17.28" (439mm) of precipitation.

Snowfall

January through May, September through December are months with snowfall. September is the first month it typically snows. Throughout September, in the average 0.2 snowfall days, it receives 0.35" (9mm) of snow. Throughout the year, there are 56.4 snowfall days, and 37.4" (950mm) of snow is accumulated.

Daylight

In Greenacres, the average length of the day in September is 12h and 33min.
On the first day of September, sunrise is at 6:08 am and sunset at 7:28 pm. On the last day of the month, sunrise is at 6:47 am and sunset at 6:29 pm PDT.

Sunshine

In September, the average sunshine is 10.1h.

UV index

In Greenacres, Washington, the average daily maximum UV index in September is 4. A UV Index reading of 3 to 5 represents a moderate threat to health from exposure to the Sun's UV rays for average individuals.
Note: A maximum UV index of 4 in September translates into the following recommendations:
Act with care - Obligation to protect against skin and eye damage is highlighted. Given the potency of the midday Sun's UV radiation, one should avoid prolonged exposure. Sun-protective clothing, a long-sleeved shirt and pants, a wide-brimmed hat, and UVA and UVB-blocking sunglasses are particularly helpful in blocking UV radiation's harmful effects. Be mindful! The reflection from snow can increase the Sun's UV radiation nearly twice.

Frequently asked questions

What are the temperatures in September?

September temperatures vary between a high-temperature of 72.5°F (22.5°C) and a low-temperature of 48.2°F (9°C). The average heat index (a.k.a. 'felt air temperature', 'apparent temperature'), which represents the influence of relative humidity on air temperature, in August is computed to be 82.4°F (28°C).

What is the average humidity in September?

In Greenacres, the average relative humidity in September is 52%.

How many days does it rain in September?

In Greenacres, in September, during 7.9 rainfall days, 0.63" (16mm) of precipitation is typically accumulated.

When does it start to snow?

September is the first month it typically snows. Throughout September, in the average 0.2 snowfall days, it receives 0.35" (9mm) of snow.

How many hours of daylight does Greenacres have in September?

In September, the average day length is 12h and 33min.

When is the sunrise / sunset in September?

On the first day of September in Greenacres, sunrise is at 6:08 am and sunset at 7:28 pm. On the last day of the month, sunrise is at 6:47 am and sunset at 6:29 pm PDT.

How many hours of sunshine does Greenacres have in September?

The average sunshine duration in September is 10.1h.

How high is the UV index in September?

In September, the average daily maximum UV index is 4. A UV Index of 3 to 5 symbolizes a moderate health threat 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
Greenacres, WA

Average temperature in September - Greenacres, WA
  • Average high temperature in September: 72.5°F

The warmest month (with the highest average high temperature) is August (83.3°F).
The month with the lowest average high temperature is December (32°F).

  • Average low temperature in September: 48.2°F

The month with the highest average low temperature is August (55.9°F).
The coldest month (with the lowest average low temperature) is December (21.9°F).

Average pressure in September
Greenacres, WA

Average pressure in September - Greenacres, WA
  • Average pressure in September: 29.96"Hg

The month with the highest atmospheric pressure is January (30.19"Hg).
The month with the lowest atmospheric pressure is August (29.91"Hg).

Average wind speed in September
Greenacres, WA

Average wind speed in September - Greenacres, WA
  • Average wind speed in September: 4.9mph

The windiest month (with the highest average wind speed) is April (6.1mph).
The calmest month (with the lowest average wind speed) is December (4.7mph).

Average humidity in September
Greenacres, WA

Average humidity in September - Greenacres, WA
  • Average humidity in September: 52%

The month with the highest relative humidity is January (91%).
The month with the lowest relative humidity is August (43%).

Average rainfall in September
Greenacres, WA

Average rainfall in September - Greenacres, WA
  • Average rainfall in September: 0.63"

The wettest month (with the highest rainfall) is January (2.28").
The driest months (with the least rainfall) are July and August (0.35").

Average rainfall days in September
Greenacres, WA

Average rainfall days in September - Greenacres, WA
  • Average rainfall days in September: 7.9 days

The month with the highest number of rainy days is March (16 days).
The month with the least rainy days is July (5.1 days).

Average snowfall in September
Greenacres, WA

Average snowfall in September - Greenacres, WA
  • Average snowfall in September: 0.35"

The month with the highest snowfall is January (10.51").
The months with the least snowfall are June, July and August (0").

Average snowfall days in September
Greenacres, WA

Average snowfall days in September - Greenacres, WA
  • Average snowfall days in September: 0.2 days

The month with the highest number of snowfall days is December (13.9 days).
The months with the least snowfall days are June, July and August (0 days).

Average daylight in September /
Average sunshine in September
Greenacres, WA

Average daylight in September / Average sunshine in September - Greenacres, WA
  • Average daylight in September: 12h and 3min

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

  • Average sunshine in September: 10h and 1min

The month with the most sunshine is August (Average sunshine: 12h and 0min).
The months with the least sunshine are January and December (Average sunshine: 3h and 48min).

Average sunshine days in September
Greenacres, WA

Average sunshine days in September - Greenacres, WA
  • Average sunshine days in September: 20.8 days

The month with the most sunshine days is July (24.3 days).
The month with the least sunshine days is March (10.3 days).

Average UV index in September
Greenacres, WA

Average UV index in September - Greenacres, WA
  • Average UV index in September: 4

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

Average cloud cover in September
Greenacres, WA

Average cloud cover in September - Greenacres, WA
  • Average cloud cover in September: 21

The month with the most cloud cover is January (Cloud cover 62).
The months with the least cloud cover are July and August (Cloud cover 13).

Average visibility in September
Greenacres, WA

Average visibility in September - Greenacres, WA
  • Average visibility in September: 6mi

The months with the highest visibility are April, May, June, July, August, September and October (6mi).
The months with the lowest visibility are January, February and December (4mi).

Greenacres, Washington, USA

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