Average Temperatures for Washington in September





Average temperatures for September at cities and other locations throughout Washington are listed below in degrees Fahrenheit and Celsius.

You can jump to a separate table for each region of the state: Olympic Peninsula & West Coast, San Juan Islands & Puget Sound, Cascade Mountains and Eastern Washington.

The tables give the normals for maximum and minimum temperatures based on weather data collected from 1991 to 2020 by the US National Centers for Environmental Information.

Olympic Peninsula & West Coast

Average September temperatures
High °F Low °F Place High °C Low °C
69 51 Aberdeen 20 11
70 46 Clearwater 21 8
70 47 Forks 21 9
68 48 Friday Harbor, San Juan Island 20 9
77 42 Grayland 25 5
66 48 Long Beach 19 9
65 51 Port Angeles 18 11

San Juan Islands, Puget Sound & South

Average daily temperatures in September
High °F Low °F Place High °C Low °C
70 51 Anacortes 21 11
68 50 Bellingham 20 10
72 51 Bremerton 22 11
73 48 Centralia 23 9
68 52 Everett 20 11
76 50 Longview 24 10
69 49 Mount Vernon 20 9
79 52 Oak Harbor, Whidbey Island 26 11
65 51 Olga, Orcas Island 18 11
72 46 Olympia 22 8
68 51 Port Townsend 20 11
72 54 Seattle 22 12
74 48 Shelton 23 9
71 53 Tacoma 22 12
74 47 Vancouver 23 8

Cascade Mountains

September temperatures: daily averages
High °F Low °F Place High °C Low °C
69 47 Baker Lake Dam 20 9
71 48 Baring 22 9
72 47 Darrington 22 9
75 42 Mt Adams Ranger Station 24 6
57 41 Mt Rainier Paradise Ranger Station 14 5
70 48 Mud Mountain Lake Dam 21 9
70 50 Ross Dam 21 10
63 47 Stampede Pass 17 8

Eastern Washington State

Average September temperatures
High °F Low °F Place High °C Low °C
73 43 Boundary Dam 23 6
77 49 Chelan 25 10
77 51 Coulee Dam 25 10
81 53 Kennewick 27 12
78 42 Leavenworth 26 5
79 47 Moses Lake 26 8
76 44 Pullman 24 7
74 49 Spokane 23 9
79 54 Walla Walla 26 12
67 50 Wenatchee 19 10
77 41 Winthrop 25 5
79 45 Yakima 26 7
Reference

NOAA National Centers for Environmental Information (NCEI). Climate Normals.

Washington Temperatures
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