Vernonia, OR Climate

Climate Insight: Vernonia, OR

Based on station USC00358884 feeding NOAA's 1991–2020 climate normals, Vernonia, Oregon averages 49°F a year, ranging from a mean daily high of 61°F to a mean daily low of 38°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.

Anyone planning to live, garden, or travel in Vernonia should weigh precipitation alongside temperature: the annual average runs 48.0 inches, with 1.1 inches typically falling as snow. The frost-free season averages 146 days, which directly shapes the planting calendar and growing potential for the area, with the last spring freeze near May 8 and the first fall freeze near October 1. And on the energy front, 5,772 heating degree days and 84 cooling degree days tell the story of how often furnaces and air conditioners run during a normal year.

On PlainClimate's composite comfort index, Vernonia scores 69/100 (Good), 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.