September weather forecast and climate
North Cascades National Park, WA

The lovely Picture Lake reflecting the trees on the shores and the distant Mount Shuksan in the North Cascades National Park, Washington, USA
The lovely Picture Lake reflecting the trees on the shores and the distant Mount Shuksan in the North Cascades National Park, Washington, USA

Weather in September

September, the first month of the autumn, in North Cascades National Park, is also an enjoyable month, with average temperature varying between 39.2°F (4°C) and 60.8°F (16°C).

Temperature

In September, the average high-temperature decreases, from an agreeable 69.8°F (21°C) in August, to an enjoyable 60.8°F (16°C). In September, in North Cascades National Park, Washington, the average low-temperature is 39.2°F (4°C).

Rainfall

In North Cascades National Park, in September, during 11 rainfall days, 2.52" (64mm) of precipitation is typically accumulated. In North Cascades National Park, during the entire year, the rain falls for 157 days and collects up to 51.02" (1296mm) of precipitation.

Daylight

In North Cascades National Park, the average length of the day in September is 12.6h.

Sunshine

In September, the average sunshine in North Cascades National Park is 6h.

UV index

In North Cascades National Park, the average daily maximum UV index in September is 5. A UV Index value of 3 to 5 symbolizes a medium health hazard from the exposure to the Sun's UV radiation for ordinary individuals.
Note: The average daily UV index of 5 transform into the following instructions:
Take precautions - Protection against the skin and eye damage is obliged. 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 temperature in September in North Cascades National Park?

The average high-temperature, in September, is 60.8°F (16°C), while the average low-temperature is 39.2°F (4°C).

How much does it rain in North Cascades National Park in September?

In North Cascades National Park, Washington, in September, during 11 rainfall days, 2.52" (64mm) of precipitation is typically accumulated.

What is the average length of the day in September in North Cascades National Park?

The average length of the day in September is 12.6h.

How many hours of sunshine does North Cascades National Park have in September?

In September, the average sunshine is 6h.

What is the UV index intensity in September in North Cascades National Park?

In September, the average daily maximum UV index is 5. A UV Index reading of 3 to 5 represents a moderate health threat from the exposure to the Sun's UV radiation.

Average temperature in September
North Cascades National Park, WA

Average temperature in September - North Cascades National Park, WA
  • Average high temperature in September: 61°F

The warmest months (with the highest average high temperature) are July and August (70°F).
Months with the lowest average high temperature are January and December (30°F).

  • Average low temperature in September: 39°F

Months with the highest average low temperature are July and August (45°F).
The coldest months (with the lowest average low temperature) are January and December (18°F).

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Average rainfall in September
North Cascades National Park, WA

Average rainfall in September - North Cascades National Park, WA
  • Average rainfall in September: 2.5"

The wettest month (with the highest rainfall) is December (7.8").
The driest months (with the least rainfall) are July and August (1.7").

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Average rainfall days in September
North Cascades National Park, WA

Average rainfall days in September - North Cascades National Park, WA
  • Average rainfall days in September: 11 days

The month with the highest number of rainy days is December (18 days).
The month with the least rainy days is July (8 days).

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Average daylight in September /
Average sunshine in September
North Cascades National Park, WA

Average daylight in September / Average sunshine in September - North Cascades National Park, WA
  • Average daylight in September: 12.6h

The month with the longest days is June (Average daylight: 16.1h).
The month with the shortest days is December (Average daylight: 8.4h).

  • Average sunshine in September: 6h

The month with the most sunshine is July (Average sunshine: 9h).
Months with the least sunshine are January, November and December (Average sunshine: 2).

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Average UV index in September
North Cascades National Park, WA

Average UV index in September - North Cascades National Park, WA
  • Average UV index in September: 5

Months with the highest UV index are June, July and August (UV index 7).
Months with the lowest UV index are January, November and December (UV index 1).

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