Natl Arboretum DC, MD Climate

Climate Insight: Natl Arboretum DC, MD

An annual average temperature of 58°F, ranging from a mean daily high of 68°F to a mean daily low of 49°F is what the NOAA 1991–2020 climate normals report for Natl Arboretum DC, Maryland. July is typically the warmest month of the year, while January is the coldest. That baseline comes from station USC00186350 and thirty years of averaging, so it reflects a typical month rather than any one year's swings.

Precipitation patterns matter as much as temperature for anyone planning to live, garden, or travel here. Natl Arboretum DC receives roughly 45.6 inches of precipitation each year, with 9.7 inches typically falling as snow. The frost-free season averages 224 days, which directly shapes the planting calendar and growing potential for the area, with the last spring freeze near March 29 and the first fall freeze near November 8. For energy use, 4,049 heating degree days and 1,649 cooling degree days tell the story of how often furnaces and air conditioners run during a normal year.

On PlainClimate's composite comfort index, Natl Arboretum DC scores 78/100 (Good), a blended measure that weighs temperature mildness, precipitation moderation, and extreme-weather frequency against one another. For planning purposes, look to the monthly tables above: shoulder seasons bring the mildest highs and lows, summer brings July-driven heat, and deep winter brings January-driven cold. Treat every figure here as a thirty-year average rather than a forecast - individual years routinely run warmer, cooler, wetter, or drier than the normal.