Washington County Climate
Washington County, Oregon
Avg Annual Temp
53.5°F
Annual Precip
41.5"
Annual Snowfall
4.0"
Extreme Heat Days
17.625
days >= 90°F/yr
Monthly Temperature
Precipitation Calendar
Seasonal Overview
National Comparison
Climate Profile
About Washington County Weather
Matching the National Average Perfectly
Washington County's average temperature of 53.5°F aligns exactly with the national median. This marine-influenced climate offers stable temperatures without the extreme fluctuations found in the Midwest.
One of Oregon’s Warmest, Wettest Hubs
The county stays 3 degrees warmer than the state average of 50.5°F. It also receives 41.5 inches of annual precipitation, outpacing the Oregon state average of 37.4 inches.
Consistent With the Willamette Valley Profile
Its climate closely mirrors Multnomah County, though it often stays slightly drier than the deepest parts of the valley. It remains warmer and more developed than the rugged coastal counties to the west.
Mild Summers and Wet, Green Winters
Summers are temperate with only 18 days above 90°F and a comfortable 66.0°F average. Winters are dominated by rain rather than ice, seeing only 4.0 inches of snow and a January average of 41.5°F.
Rain Gear is the Primary Priority
With 41.5 inches of annual rain, high-quality waterproof gear is essential for daily life. Since extreme heat is limited to just 18 days, many residents prioritize moisture control and drainage over heavy-duty air conditioning.
Frequently Asked Questions
What is the average temperature in Washington County?
How much rain does Washington County get?
Does it snow in Washington County?
How hot does Washington County get in summer?
How cold are winters in Washington County?
Track your own weather in Washington County
Ambient Weather personal weather stations give you hyperlocal climate data.
Sponsored
Data source: NOAA National Centers for Environmental Information (NCEI), U.S. Climate Normals 1991-2020.
Climate normals are 30-year averages of weather variables computed from 1991 to 2020. Station data is aggregated to county level using spatial averaging. Data is informational only — not a substitute for official National Weather Service forecasts or emergency weather warnings.