Average Precipitation for Washington in September
The tables below give monthly averages for rainfall plus snowfall during September at cities and other locations in Washington.
Each place has a total for the amount of precipitation it usually receives this month. There is also information on the number of days with wet weather. That includes the days when precipitation amounts to 0.01 inches (0.25 millimetres) or more.
The precipitation totals are averages based on weather data collected from 1991 to 2020 for the US National Centers for Environmental Information.
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.
Olympic Peninsula & West Coast
| Days | Place | Inches | Millimetres |
|---|---|---|---|
| 9 | Aberdeen | 2.7 | 69 |
| 10 | Clearwater | 4.8 | 122 |
| 12 | Forks | 4.8 | 121 |
| 12 | Friday Harbor, San Juan Island | 1.0 | 26 |
| 10 | Grayland | 2.9 | 75 |
| 12 | Long Beach | 2.7 | 68 |
| 8 | Port Angeles | 1.2 | 31 |
San Juan Islands, Puget Sound & South
| Days | Place | Inches | Millimetres |
|---|---|---|---|
| 8 | Anacortes | 1.6 | 39 |
| 11 | Bellingham | 2.0 | 51 |
| 9 | Bremerton | 1.8 | 46 |
| 8 | Centralia | 1.6 | 40 |
| 13 | Everett | 1.7 | 43 |
| 9 | Longview | 2.3 | 58 |
| 10 | Oak Harbor, Whidbey Island | 1.1 | 27 |
| 7 | Olga, Orcas Island | 1.6 | 41 |
| 8 | Olympia | 2.0 | 52 |
| 7 | Port Townsend | 1.1 | 28 |
| 8 | Seattle | 1.6 | 41 |
| 9 | Shelton | 2.5 | 64 |
| 7 | Tacoma | 1.6 | 40 |
| 8 | Vancouver | 1.6 | 41 |
Cascade Mountains
| Days | Place | Inches | Millimetres |
|---|---|---|---|
| 11 | Baker Lake Dam | 4.8 | 123 |
| 11 | Baring | 4.8 | 122 |
| 11 | Ross Dam | 2.5 | 64 |
Eastern Washington State
| Days | Place | Inches | Millimetres |
|---|---|---|---|
| 8 | Boundary Dam | 1.3 | 34 |
| 2 | Chelan | 0.3 | 9 |
| 4 | Coulee Dam | 0.4 | 9 |
| 3 | Kennewick | 0.3 | 7 |
| 4 | Leavenworth | 0.8 | 19 |
| 3 | Moses Lake | 0.3 | 7 |
| 5 | Pullman | 0.7 | 17 |
| 5 | Spokane | 0.6 | 15 |
| 4 | Walla Walla | 0.6 | 16 |
| 2 | Wenatchee | 0.2 | 6 |
| 4 | Winthrop | 0.5 | 11 |
| 3 | Yakima | 0.2 | 6 |
Reference
NOAA National Centers for Environmental Information (NCEI). Climate Normals.