District of Columbia Geography & Climate

The District was laid out as a perfect diamond, ten miles on each side, its corners set to the compass points — a hundred square miles taken from Maryland on the east bank and Virginia on the west.

The Virginia third was returned in 1847, which is why the diamond is now cut off along the river and the District covers about 68 square miles rather than a hundred. Several of the original boundary stones still stand.

It sits at the fall line, where the coastal plain meets harder piedmont rock and the Potomac stops being navigable — the reason for a settlement here at all.

Ground is low along the rivers and rises north and east; Tenleytown, at about 400 feet, is the high point. Much of the monumental core is nineteenth-century reclaimed riverbed.

The District has a humid subtropical climate. Summers are its defining feature — hot, humid and thundery from late June into September, made worse by the low riverside setting.

Winters are mild by American standards, with occasional snow the District handles poorly; a few inches slows everything.

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

Remnants of Atlantic hurricanes occasionally arrive in late summer, bringing rain rather than damaging wind.