San Luis Obispo, CA Climate

Climate Insight: San Luis Obispo, CA

The NOAA 1991–2020 climate normals describe San Luis Obispo, California as a location with an annual average temperature of 60°F, ranging from a mean daily high of 72°F to a mean daily low of 47°F. August is typically the warmest month of the year, while December is the coldest. These thirty-year averages, computed from station USW00093206, 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. San Luis Obispo receives roughly 17.9 inches of precipitation each year, predominantly as rainfall. The frost-free season averages 314 days, which directly shapes the planting calendar and growing potential for the area, with the last spring freeze near January 31 and the first fall freeze near December 11. For energy use, 2,265 heating degree days and 334 cooling degree days tell the story of how often furnaces and air conditioners run during a normal year.

On PlainClimate's composite comfort index, San Luis Obispo scores 75/100 (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.