Avg. Humidity: 71%
Humidity & Mold in Washington
Western Washington receives 37-60 inches of rain annually with overcast skies 200+ days per year. Chronic moisture problems differ from the South — less dramatic but more persistent. Crawl spaces and attics are particularly vulnerable.
71%
Avg. Humidity
Oceanic (west) / Semi-arid (east)
Climate
High
Humidity Level
7.9M
Population
Top Moisture Issues in Washington
Persistent rain-driven moisture
Bathroom mold
Crawl space rot
Exterior moss and mildew
Expert Tips for Washington Homeowners
1
Direct gutters 6+ ft from foundation
2
Install powered crawl space ventilation
3
Run dehumidifier October–April
4
Check attic for condensation annually
5
Apply moss killer every spring
