Weather in Washington in August

Shoulder season. August sits in between. You will get good days and you will lose some. Highs average 30.6 °C, lows 20.6 °C, and rain falls on 13 days — nothing in the month is working against you.

August ranks 7 of 12 in Washington: past the worst of the year but short of October, which is the month to book if the dates are open.

Rain on 13 days, 3 of them heavy. Enough to need a plan B, not enough to need a plan around it. Pack for 30.6 °C days and 20.6 °C nights; the spread matters more here than any single number.

What the averages hide

Averages flatten a month, and this one hides a few things: 18 days top 30 °C — hot spells arrive, but they break. Across the twenty years measured, the hottest August day reached 38.2 °C and the coldest night fell to 13.6 °C, and the wettest single day dropped 95 mm — roughly 86% of the month's rain in one day.

August is moderately variable: 30 mm in the driest year against 244 mm in the wettest, around an average of 110 mm. Roughly two Augusts in three land near that average, and the third does something else entirely.

Wind is light at 7.1 km/h, so the temperature on the page is close to the temperature on your skin, and humidity is unremarkable at 70%.

How August sits in the year

Temperatures hold steady either side: 31.1 °C in July, 30.6 here, 27.1 in September. Nothing about the timing within the month matters much.

Daylight in August

13.7 hours of daylight, losing 1.1 hours across the month. That is between Washington's extremes of 14.9 and 9.5 hours, so days are long enough not to constrain the plan.

An inland climate

With no coast nearby, the year swings a fair way — 34.4 °C between the warmest afternoons and the coldest nights, wider than any coastal city at this latitude would manage.

How busy it gets

Busy. Popular without being frantic; book the things you care about, improvise the rest.

Crowd levels are estimated from climate desirability and school-holiday calendars, not from visitor numbers.

August in Washington versus nearby

If Washington is one option among several, the nearby comparison is worth making. Richmond is a better bet in August — 9.1 °C cooler, 8 days less rain. Philadelphia is close enough to be a coin toss — within a degree on temperature, the same number of rain days.

So: August is a compromise. October is 22 points better and is what Washington is actually like at its best — worth moving the trip for if that is possible, and worth adjusting expectations for if it is not.

Every month in Washington

See all twelve months in Washington, or where else to go in August.