ST John, WA Climate

Climate Insight: ST John, WA

An annual average temperature of 49°F, ranging from a mean daily high of 59°F to a mean daily low of 40°F is what the NOAA 1991–2020 climate normals report for ST John, Washington. July is typically the warmest month of the year, while December is the coldest. That baseline comes from station USC00457267 and thirty years of averaging, so it reflects a typical month rather than any one year's swings.

ST John averages 17.1 inches of precipitation a year, with 26.6 inches typically falling as snow, and that matters as much to daily life here as temperature does. The frost-free season averages 158 days, which directly shapes the planting calendar and growing potential for the area, with the last spring freeze near April 29 and the first fall freeze near October 4. As for energy demand, 6,085 heating degree days and 375 cooling degree days tell the story of how often furnaces and air conditioners run during a normal year.

On PlainClimate's composite comfort index, ST John scores 49/100 (Moderate), a blended measure that weighs temperature mildness, precipitation moderation, and extreme-weather frequency against one another. Shoulder seasons bring the mildest highs and lows in the monthly tables above, summer brings July-driven heat, and winter brings December-driven cold - use that rhythm for planning. These figures are thirty-year averages rather than forecasts, so a specific year may still run warmer, cooler, wetter, or drier than what's shown.