Rockville, MD Climate

Climate Insight: Rockville, MD

Based on station USC00187705 feeding NOAA's 1991–2020 climate normals, Rockville, Maryland averages 56°F a year, ranging from a mean daily high of 65°F to a mean daily low of 47°F. July is typically the warmest month of the year, while January 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.

Rockville averages 41.3 inches of precipitation a year, predominantly as rainfall, and that matters as much to daily life here as temperature does. The frost-free season averages 219 days, which directly shapes the planting calendar and growing potential for the area, with the last spring freeze near April 1 and the first fall freeze near November 6. As for energy demand, 4,455 heating degree days and 1,279 cooling degree days tell the story of how often furnaces and air conditioners run during a normal year.

On PlainClimate's composite comfort index, Rockville scores 78/100 (Good), 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 January-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.