Temperature in Washington State in September

Daytime highs, nighttime lows and the warmest cities in Washington State, the United States of America this September.

Washington State, the United States of America, a region in the United States of America, experiences maximum daytime temperatures in September ranging from 8°C (46°F) in Mount Rainier National Park to 27°C (81°F) in Pasco. Nighttime temperatures generally drop to 10°C (50°F) in Pasco and -3°C (27°F) in Mount Rainier National Park. The month of September is in the summer season.

What is the temperature of the different cities in Washington State, the United States of America in September?

To get a sense of September's typical temperatures in the key spots of Washington State, explore the map below. Click on a point for an in-depth look.

Select a Month

Check the conditions for any month of the year.

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For a detailed overview over the year and the best time to visit Washington State, check out our Washington State's climate page.

See also: Washington State weather by month.

Best Places to Visit in Washington State in September

Click on a destination dot for more details. Toggle the map to compare temperatures or precipitation across Washington State.

Conditions Temperatures Precipitation
Avg daytime high -5°C (23°F) cold → 32°C (90°F) hot

Marker color shows the average daytime high temperature in September: blue is cold, red is hot.

See all September weather averages, cities and regions in Washington State

Washington State temperatures in September: frequently asked questions

How hot does it get in Washington State, the United States of America in September?

Average daytime highs in Washington State, the United States of America during September reach about 22°C (72°F) in Seattle.

How cold does it get at night in Washington State, the United States of America in September?

After dark, Seattle cools to about 12°C (54°F) on an average September night.

What is the warmest city in September in Washington State, the United States of America?

Data insights from our comprehensive database indicate that Pasco is the city with the highest warmth. Daytime peaks average near 27°C (81°F), while the nights are characterized by a low temperature close to 10°C (50°F).

What is the coldest city in September in Washington State, the United States of America?

When looking through our records, we find that Mount Rainier National Park stands out as the coolest city in Washington State, the United States of America for the month of September. Daytime highs average 8°C (46°F) and it cools down to about -3°C (27°F) at night.

How much sun does Washington State, the United States of America get in September?

Across Washington State, the United States of America, sunshine in September ranges from moderately sunny in Bellingham (188 hours) to sunny in Spokane (272 hours).

Interested in more climate information?

We have much more information about the climate in Washington State.

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