Rosalia, WA Climate

Climate Insight: Rosalia, WA

Based on station USC00457180 feeding NOAA's 1991–2020 climate normals, Rosalia, Washington averages 48°F a year, ranging from a mean daily high of 60°F to a mean daily low of 37°F. August is typically the warmest month of the year, while December is the coldest. Because these figures are thirty-year averages rather than any single year's readings, they describe the typical month, not a forecast for it.

Beyond temperature, Rosalia averages 18.4 inches of precipitation annually, with 26.2 inches typically falling as snow - a real factor for anyone planning to live, garden, or travel here. The frost-free season averages 144 days, which directly shapes the planting calendar and growing potential for the area, with the last spring freeze near May 7 and the first fall freeze near September 28. Turning to energy use, 6,509 heating degree days and 377 cooling degree days tell the story of how often furnaces and air conditioners run during a normal year.

On PlainClimate's composite comfort index, Rosalia scores 49/100 (Moderate), a blended measure that weighs temperature mildness, precipitation moderation, and extreme-weather frequency against one another. The monthly tables above turn that into a planning tool: expect the mildest highs and lows in the shoulder seasons, August-driven heat at the peak of summer, and December-driven cold at the depth of winter. Every number here is a thirty-year average, not a forecast, so any given year can and does run warmer, cooler, wetter, or drier than the normal.