Washington D.C. Geography & Climate

Washington sits at the confluence of the Potomac and the Anacostia, at the point where the coastal plain meets the harder rock of the piedmont — the fall line, which is why the river is navigable to here and no further.

The original district was a perfect diamond, ten miles on each side, taken from Maryland and Virginia. The Virginia portion was returned in 1847, which is why the shape is now cut off along the river.

Much of the monumental core is built on reclaimed ground: the Tidal Basin and the land beneath the Lincoln and Jefferson memorials were dredged from the river in the nineteenth century, and the low, wet setting is why summers feel as they do.

The 1910 Height of Buildings Act limits building heights relative to street width, which is why there are no towers and why the Capitol and the Washington Monument still dominate every view.

Washington has a humid subtropical climate, and the summers are its defining feature — hot, humid and thundery from late June into September, with the low riverside setting making it feel worse than the temperature reads.

Winters are mild by American standards, with occasional snow that the city is poorly equipped for; a few inches can close schools and slow the Metro.

Spring and autumn are excellent and short. The cherry blossom marks the start of spring and shifts by up to two weeks either side of the first of April depending on the winter.

Hurricane remnants occasionally reach the city in late summer, bringing rain rather than wind.