Pasco Tri Cities, WA Climate

Climate Insight: Pasco Tri Cities, WA

The NOAA 1991–2020 climate normals describe Pasco Tri Cities, Washington as a location with an annual average temperature of 53°F, ranging from a mean daily high of 66°F to a mean daily low of 40°F. July is typically the warmest month of the year, while December is the coldest. These thirty-year averages, computed from station USW00024163, smooth out year-to-year variability and give a baseline expectation for typical conditions in any given month.

Precipitation patterns matter as much as temperature for anyone planning to live, garden, or travel here. Pasco Tri Cities receives roughly 7.6 inches of precipitation each year, predominantly as rainfall. Growing-season length varies with elevation and microclimate, with the last spring freeze near April 27 and the first fall freeze near October 11. For energy use, 5,011 heating degree days and 788 cooling degree days tell the story of how often furnaces and air conditioners run during a normal year.

On PlainClimate's composite comfort index, Pasco Tri Cities scores 47/100 (Moderate), a blended measure that weighs temperature mildness, precipitation moderation, and extreme-weather frequency against one another. Use the monthly tables above to plan around specific windows — shoulder seasons for mild highs and lows, peak summer for July-driven heat, or deep winter for December-driven cold. All figures here are thirty-year averages: any single year may run warmer, wetter, drier, or cooler than the normal, so treat them as planning guidance rather than forecasts.