September weather forecast
South Cle Elum, WA

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Weather in September

The first month of the autumn, September, is still a refreshing month in South Cle Elum, Washington, with temperature in the range of an average high of 64.6°F (18.1°C) and an average low of 42.3°F (5.7°C).

Temperature

September implies a gentle temperature shift, with average high-temperatures reducing from August's moderately hot 75.4°F (24.1°C) to an enjoyable 64.6°F (18.1°C). South Cle Elum's average nighttime temperature descends significantly from the day's peak in September, settling at a cold 42.3°F (5.7°C).

Humidity

In September, the average relative humidity is 68%.

Rainfall

In South Cle Elum, during September, the rain falls for 10.7 days and regularly aggregates up to 1.1" (28mm) of precipitation. Throughout the year, there are 161.2 rainfall days, and 28.46" (723mm) of precipitation is accumulated.

Snowfall

Months with snowfall are January through May, September through December. September is the first month it typically snows. Throughout September, in the average 0.2 snowfall days, it receives 0.2" (5mm) of snow. In South Cle Elum, during the entire year, snow falls for 69.9 days and aggregates up to 60.24" (1530mm) of snow.

Daylight

In South Cle Elum, the average length of the day in September is 12h and 32min.
On the first day of September, sunrise is at 6:24 am and sunset at 7:42 pm. On the last day of the month, sunrise is at 7:02 am and sunset at 6:44 pm PDT.

Sunshine

The average sunshine in September is 10.2h.

UV index

The average daily maximum UV index in September is 3. A UV Index estimate of 3 to 5 represents a medium health hazard from unsafe exposure to UV radiation for the ordinary person.
Note: In September, an average UV index of 3 transforms into the following instructions:
Guard yourself - Avoiding sunburn is suggested. The solar radiation is most powerful near the mid-day, so the exposure to the direct Sun should be reduced accordingly. Select sunglasses that boast both UVA and UVB protection to limit the adverse effects of the sun on the eyes. Be cautious! The UV radiation from the Sun can be magnified almost twofold by snow reflection.
Updated: Jul 24, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the average September temperature?

The average high-temperature and low-temperature during September are 64.6°F (18.1°C) and 42.3°F (5.7°C) respectively.

What is the average humidity in September?

In South Cle Elum, the average relative humidity in September is 68%.

How many days does it rain in September?

In South Cle Elum, in September, during 10.7 rainfall days, 1.1" (28mm) 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 0.2" (5mm) of snow.

What is the average length of the day in September?

In September, the average day length is 12h and 32min.

When is the sunrise / sunset in September?

On the first day of September, sunrise is at 6:24 am and sunset at 7:42 pm. On the last day of the month, sunrise is at 7:02 am and sunset at 6:44 pm PDT.

How long on average sun shines in September?

In South Cle Elum, the average sunshine duration in September is 10.2h.

What is the UV index reading in September?

The average daily maximum UV index in September is 3. 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
South Cle Elum, WA

Average temperature in September - South Cle Elum, WA
  • Average high temperature in September: 64.6°F

The warmest month (with the highest average high temperature) is August (75.4°F).
The month with the lowest average high temperature is December (29.7°F).

  • Average low temperature in September: 42.3°F

The month with the highest average low temperature is August (47.8°F).
The coldest month (with the lowest average low temperature) is December (18.3°F).

Average pressure in September
South Cle Elum, WA

Average pressure in September - South Cle Elum, WA
  • Average pressure in September: 29.98"Hg

The month with the highest atmospheric pressure is January (30.14"Hg).
The month with the lowest atmospheric pressure is August (29.96"Hg).

Average wind speed in September
South Cle Elum, WA

Average wind speed in September - South Cle Elum, WA
  • Average wind speed in September: 5.3mph

The windiest month (with the highest average wind speed) is June (6.7mph).
The calmest month (with the lowest average wind speed) is December (4.2mph).

Average humidity in September
South Cle Elum, WA

Average humidity in September - South Cle Elum, WA
  • Average humidity in September: 68%

The months with the highest relative humidity are January and February (92%).
The months with the lowest relative humidity are July and August (60%).

Average rainfall in September
South Cle Elum, WA

Average rainfall in September - South Cle Elum, WA
  • Average rainfall in September: 1.1"

The wettest month (with the highest rainfall) is January (4.41").
The driest month (with the least rainfall) is July (0.39").

Average rainfall days in September
South Cle Elum, WA

Average rainfall days in September - South Cle Elum, WA
  • Average rainfall days in September: 10.7 days

The months with the highest number of rainy days are March and April (18.3 days).
The month with the least rainy days is August (5.5 days).

Average snowfall in September
South Cle Elum, WA

Average snowfall in September - South Cle Elum, WA
  • Average snowfall in September: 0.2"

The month with the highest snowfall is January (16.3").
The months with the least snowfall are June, July and August (0").

Average snowfall days in September
South Cle Elum, WA

Average snowfall days in September - South Cle Elum, WA
  • Average snowfall days in September: 0.2 days

The month with the highest number of snowfall days is December (15.1 days).
The months with the least snowfall days are June, July and August (0 days).

Average daylight in September /
Average sunshine in September
South Cle Elum, WA

Average daylight in September / Average sunshine in September - South Cle Elum, 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 36min).

  • Average sunshine in September: 10h and 1min

The month with the most sunshine is August (Average sunshine: 11h and 54min).
The month with the least sunshine is January (Average sunshine: 3h and 24min).

Average sunshine days in September
South Cle Elum, WA

Average sunshine days in September - South Cle Elum, WA
  • Average sunshine days in September: 16.3 days

The month with the most sunshine days is August (22.8 days).
The month with the least sunshine days is February (6.8 days).

Average UV index in September
South Cle Elum, WA

Average UV index in September - South Cle Elum, WA
  • Average UV index in September: 3

The month with the highest UV index is July (UV index 5).
The months with the lowest UV index are January, February, November and December (UV index 1).

Average cloud cover in September
South Cle Elum, WA

Average cloud cover in September - South Cle Elum, WA
  • Average cloud cover in September: 30

The month with the most cloud cover is January (Cloud cover 63).
The months with the least cloud cover are July and August (Cloud cover 18).

Average visibility in September
South Cle Elum, WA

Average visibility in September - South Cle Elum, WA
  • Average visibility in September: 6mi

The months with the highest visibility are May, June, July, August and September (6mi).
The month with the lowest visibility is January (3mi).

South Cle Elum, Washington, USA

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