Mason County Climate
Mason County, Washington
NOAA NCEI 1991-2020 Climate NormalsAvg Annual Temp
51.3°F
Annual Precip
83.3"
Annual Snowfall
3.2"
Extreme Heat Days
6
days >= 90°F/yr
Monthly Temperature
Precipitation Calendar
Growing Season & Gardening
8b
Minimum winter temperature range for plant survival
1,836
Favors cool-season crops
Seasonal Overview
National Comparison
7-Day Outlook
Forecast
Current Conditions
Air Quality
Safety
Weather Alerts
Climate Advisory: Mason County
Climate Verdict
Mason County has a mild, with an average annual temperature of 51.3°F, very wet conditions receiving 83.3 inches of precipitation annually, rare extreme heat with only 6 days above 90°F annually, light snow averaging 3.2 inches per year. This climate profile shapes everything from energy costs to outdoor recreation opportunities.
Seasonal Breakdown
Winters are mild, with January temperatures averaging 40.6°F. summers are pleasantly cool with July averaging 64.7°F. The climate is remarkably stable year-round, with only a 24°F difference between January and July. December is typically the coldest month and August the warmest.
Outdoor & Gardening Guidance
Growing season and gardening data is currently limited for Mason County. Check the USDA Plant Hardiness Zone Map and local extension office for specific guidance.
Regional Context
Mason County closely matches the Washington statewide average temperature of 49.9°F, it is also noticeably wetter, receiving 44.7 inches more precipitation than the state average.
Climate Profile
About Mason County Weather
A Very Wet Marine Climate
Mason County's 51.3°F average temperature is typical for the region, but its precipitation is extreme by national standards. The county is defined by its high moisture and moderate temperatures.
Double the State Average Rainfall
The county receives a staggering 83.3 inches of precipitation annually, more than double the state average of 38.5 inches. Its 51.3°F temperature is slightly warmer than the state mean.
The Rain Capital of the Region
Mason's 83.3 inches of rain dwarfs King County's 64.2 inches and Kitsap's 56.9 inches. However, it stays very similar in temperature to its Puget Sound neighbors.
Rainy Winters and Mild Summers
Snow is rare here, with only 3.2 inches falling annually. Summers are very comfortable with a July average of 64.7°F and only 6 days of extreme heat per year.
Invest in Quality Rain Gear
With 83.3 inches of rain, residents should prioritize roof maintenance and high-end waterproof clothing. Air conditioning is rarely a necessity given the consistent marine cooling.
Frequently Asked Questions
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Data sources: NOAA National Centers for Environmental Information (NCEI), U.S. Climate Normals 1991-2020. Forecast and alert data from National Weather Service API. Air quality data from Open-Meteo.
Climate normals are 30-year averages of weather variables. Station data is aggregated to county level. Forecasts and alerts are fetched live and may change frequently. Data is informational only — not a substitute for official National Weather Service forecasts or emergency weather warnings.