September weather forecast
Mount Rainier National Park, WA

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A beautiful reflection in the clear waterfront of the trees and snowy mountain in Mount Rainier National Park, Washington
A beautiful reflection in the clear waterfront of the trees and snowy mountain in Mount Rainier National Park, Washington

Weather in September

The arrival of September invites a gradual shift towards the forthcoming fall season in Mount Rainier National Park. As temperatures gently dip, September retains the summer's warmth, offering pleasant days and cool, comfortable nights. The return of snowfall at 1.4" (36mm) is the month's most significant change. This discrete announcement of incoming colder times rarely obstructs outdoor activities. Enthusiasts can witness the beginnings of the foliage’s color transition towards autumnal hues.

Temperature

The average high-temperature shows a slight dip in September, from August's comfortable 64.6°F (18.1°C) to a mild 58.1°F (14.5°C). An average nighttime temperature of 39.7°F (4.3°C) is recorded during September.

Rainfall

In Mount Rainier National Park, Washington, in September, it is raining for 9.6 days, with typically 4.72" (120mm) of accumulated precipitation. Throughout the year, in Mount Rainier National Park, there are 188.7 rainfall days, and 118.31" (3005mm) of precipitation is accumulated.

Snowfall

January through December are months with snowfall. In Mount Rainier National Park, during September, snow falls for 0.7 days and regularly aggregates up to 1.42" (36mm) of snow. Throughout the year, in Mount Rainier National Park, Washington, there are 121.5 snowfall days, and 670.91" (17041mm) of snow is accumulated.

Daylight

The average length of the day in September is 12h and 32min.
On the first day of the month, sunrise is at 6:27 am and sunset at 7:45 pm. On the last day of September, in Mount Rainier National Park, sunrise is at 7:05 am and sunset at 6:47 pm PDT.
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Frequently asked questions

What are the temperatures in Mount Rainier National Park in September?

The high-temperature, in September, in Mount Rainier National Park, records 58.1°F (14.5°C), while the low-temperature is 39.7°F (4.3°C).

How many days does it rain in September in Mount Rainier National Park?

In Mount Rainier National Park, during September, the rain falls for 9.6 days and regularly aggregates up to 4.72" (120mm) of precipitation.

How many days does it snow in September in Mount Rainier National Park?

In Mount Rainier National Park, Washington, in September, snow falls for 0.7 days, with typically accumulated 1.42" (36mm) of snow.

What is the average length of the day in September in Mount Rainier National Park?

The average day length in September in Mount Rainier National Park, Washington, is 12h and 32min.

What time are sunrise and sunset in September in Mount Rainier National Park?

On the first day of September in Mount Rainier National Park, sunrise is at 6:27 am and sunset at 7:45 pm. On the last day of the month, sunrise is at 7:05 am and sunset at 6:47 pm PDT.
Average rainfall days
Average snowfall days
Average daylight

Average temperature in September
Mount Rainier National Park, WA

Average temperature in September - Mount Rainier National Park, WA
  • Average high temperature in September: 58.1°F

The warmest month (with the highest average high temperature) is August (64.5°F).
The month with the lowest average high temperature is December (33.8°F).

  • Average low temperature in September: 39.7°F

The month with the highest average low temperature is August (43.9°F).
The coldest month (with the lowest average low temperature) is December (21.1°F).

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Average rainfall in September
Mount Rainier National Park, WA

Average rainfall in September - Mount Rainier National Park, WA
  • Average rainfall in September: 4.7"

The wettest month (with the highest rainfall) is November (20.3").
The driest months (with the least rainfall) are July and August (2").

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Average rainfall days in September
Mount Rainier National Park, WA

Average rainfall days in September - Mount Rainier National Park, WA
  • Average rainfall days in September: 9.6 days

The month with the highest number of rainy days is November (21.7 days).
The month with the least rainy days is August (6.6 days).

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Average snowfall in September
Mount Rainier National Park, WA

Average snowfall in September - Mount Rainier National Park, WA
  • Average snowfall in September: 1.4"

The months with the highest snowfall are January, November and December (99.9").
The month with the least snowfall is August (0.1").

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Average snowfall days in September
Mount Rainier National Park, WA

Average snowfall days in September - Mount Rainier National Park, WA
  • Average snowfall days in September: 0.7 days

The month with the highest number of snowfall days is March (19.5 days).
The month with the least snowfall days is August (0.1 days).

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Average daylight in September
Mount Rainier National Park, WA

Average daylight in September - Mount Rainier National Park, WA
  • Average daylight in September: 12h and 3min

The month with the longest days is June (Average daylight: 15h and 48min).
The month with the shortest days is December (Average daylight: 8h and 36min).

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Mount Rainier National Park, Washington, USA

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