September weather forecast
Leavenworth, WA

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A bridge across a small river heads up to the classy Posthotel in Leavenworth, Washington
A bridge across a small river heads up to the classy Posthotel in Leavenworth, Washington

Weather in September

September brings forth a gradual decline in warmth as Leavenworth transitions into the season of Autumn. The first hints of a cooler climate are glimpsed with a drop in temperatures, although staying at a comfortable range. The city evidences an increase in rainfall marking a detectable decrease in sunlight hours. There may be an occasional appearance of gusty winds matched with a slight uptick in humidity. Typically regarded as the onset of Fall, September conveys more cooler and comfortable days to Leavenworth.

Temperature

The average high-temperature decreases in September, shifting from a moderately hot 77.5°F (25.3°C) in August to an enjoyable 66.4°F (19.1°C). Leavenworth encounters a substantial decline from its daily high to a low-temperature of 43.2°F (6.2°C) during September nights.

Humidity

The average relative humidity in September is 65%.

Rainfall

In Leavenworth, during September, the rain falls for 10.3 days and regularly aggregates up to 1.06" (27mm) of precipitation. Throughout the year, there are 159.9 rainfall days, and 25.63" (651mm) of precipitation is accumulated.

Snowfall

Months with snowfall in Leavenworth 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 0.39" (10mm) of snow. In Leavenworth, during the entire year, snow falls for 73.4 days and aggregates up to 57.99" (1473mm) of snow.

Daylight

In September, the average length of the day is 12h and 33min.
On the first day of September, sunrise is at 6:22 am and sunset at 7:42 pm. On the last day of the month, sunrise is at 7:01 am and sunset at 6:43 pm PDT.

Sunshine

The average sunshine in September is 10.5h.

UV index

In September, the average daily maximum UV index is 3. A UV Index of 3 to 5 symbolizes a moderate health risk from exposure to the Sun's UV rays for the ordinary person.
Note: An average UV index of 3 in September transforms into this advice:
Take precautions. Light skin individuals may get burned in less than 30 minutes. UV radiation is strongest from the Sun during midday; protect yourself by staying in shaded areas. For holistic sun protection encompassing the eyes, ears, face, and neck, a wide-brim hat is key. Guard yourself! Snow reflection can almost double the UV radiation from the Sun.

Frequently asked questions

What is the usual temperature for Leavenworth in September?

The average high-temperature and low-temperature during September are 66.4°F (19.1°C) and 43.2°F (6.2°C) respectively.

What is the average humidity in September?

The average relative humidity in September is 65%.

How much does it rain in September?

In September, the rain falls for 10.3 days. Throughout September, 1.06" (27mm) of precipitation is accumulated.

When does it start snowing?

September is the first month it typically snows in Leavenworth, Washington. Throughout September, in the average 0.2 snowfall days, it receives 0.39" (10mm) of snow.

How many hours of daylight does Leavenworth have in September?

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

When is the sunrise / sunset in September?

In September, on the first day of the month, sunrise is at 6:22 am and sunset at 7:42 pm. On the last day of the month, sunrise is at 7:01 am and sunset at 6:43 pm PDT.

How long on average sun shines in September?

The average sunshine duration in September is 10.5h.

What is the UV index intensity in September?

The average daily maximum UV index in September is 3. A UV Index reading of 3 to 5 represents a moderate health threat from exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in September
Leavenworth, WA

Average temperature in September - Leavenworth, WA
  • Average high temperature in September: 66.4°F

The warmest month (with the highest average high temperature) is August (77.5°F).
The month with the lowest average high temperature is December (30.6°F).

  • Average low temperature in September: 43.2°F

The month with the highest average low temperature is August (49.6°F).
The coldest month (with the lowest average low temperature) is December (18.7°F).

Average pressure in September
Leavenworth, WA

Average pressure in September - Leavenworth, 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 (29.95"Hg).

Average wind speed in September
Leavenworth, WA

Average wind speed in September - Leavenworth, WA
  • Average wind speed in September: 4.7mph

The windiest month (with the highest average wind speed) is June (5.7mph).
The calmest month (with the lowest average wind speed) is December (3.5mph).

Average humidity in September
Leavenworth, WA

Average humidity in September - Leavenworth, WA
  • Average humidity in September: 65%

The month with the highest relative humidity is January (92%).
The months with the lowest relative humidity are July and August (56%).

Average rainfall in September
Leavenworth, WA

Average rainfall in September - Leavenworth, WA
  • Average rainfall in September: 1.06"

The wettest month (with the highest rainfall) is January (4.33").
The driest month (with the least rainfall) is July (0.43").

Average rainfall days in September
Leavenworth, WA

Average rainfall days in September - Leavenworth, WA
  • Average rainfall days in September: 10.3 days

The month with the highest number of rainy days is March (18.2 days).
The month with the least rainy days is August (6.3 days).

Average snowfall in September
Leavenworth, WA

Average snowfall in September - Leavenworth, WA
  • Average snowfall in September: 0.39"

The month with the highest snowfall is January (16.73").
The months with the least snowfall are June, July and August (0").

Average snowfall days in September
Leavenworth, WA

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

The month with the highest number of snowfall days is December (17 days).
The months with the least snowfall days are June, July and August (0 days).

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

Average daylight in September / Average sunshine in September - Leavenworth, 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 3min

The month with the most sunshine is August (Average sunshine: 11h and 54min).
The month with the least sunshine is January (Average sunshine: 4h and 6min).

Average sunshine days in September
Leavenworth, WA

Average sunshine days in September - Leavenworth, WA
  • Average sunshine days in September: 16.5 days

The month with the most sunshine days is August (21.9 days).
The month with the least sunshine days is February (6.8 days).

Average UV index in September
Leavenworth, WA

Average UV index in September - Leavenworth, WA
  • Average UV index in September: 3

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

Average cloud cover in September
Leavenworth, WA

Average cloud cover in September - Leavenworth, WA
  • Average cloud cover in September: 25

The month with the most cloud cover is January (Cloud cover 56).
The month with the least cloud cover is August (Cloud cover 15).

Average visibility in September
Leavenworth, WA

Average visibility in September - Leavenworth, 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, March, November and December (4mi).

Leavenworth, Washington, USA

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