Updated 4 Aug 2026 · recomputed nightly

Visiting Washington, D.C. in September 2026?

September 2026 is a shoulder month in Washington, D.C.: warm and wet, around 26°C / 80°F with rain on about 9 days, Lively every day.

In short, a solid middle-ground pick.

Among the 12 months we forecast for Washington, D.C., September ranks 6th for crowd pressure. Its heaviest day is Mon 7 Sep, busier than 58% of the year; its lightest is Tue 1 Sep at 49%.

Crowds

Lively · all 30

0 calm · 30 lively

Weather

26°C / 80°F

rain ~9 days

Value

A fair balance

a solid middle-ground pick

Preparing pays off in a month like this: timed-entry tickets and pre-booked tours turn the queue time into sightseeing time. see the options →

How busy is Washington, D.C. in September?

It's quiet right through September — no crowded stretch to plan around.

The month barely moves — every day lands between 49% and 58% of the year. Daylight runs about 12 hours.

Either side of it, August picks up and October picks up.

The calmest days include the 1st, 2nd and 3rd — 29 days share that level, so there is room to choose.

BEST149%BEST249%BEST349%449%549%649%758%849%949%1049%1149%1249%1349%1449%1549%1649%1749%1849%1949%2049%2149%2249%2349%2449%2549%2649%2749%2849%2949%3049%

CalmLivelyBusyPacked% = busier than this share of the year · tap any day for its full forecast

Best daysTue 1 · Wed 2 · Thu 3 — The calmest days include the 1st, 2nd and 3rd — 29 days share that level, so there is room to choose.

How does October compare? →

September weather in Washington, D.C.

Comfortably warm — around 26°C / 80°F, easy shirtsleeve weather, with rain on about 9 days, so keep a layer handy.

Washington, D.C. gets rain on about 9 days in September, so the odds of being caught out are real. What earns its bag space is a shell that packs to nothing, dries fast and has a hood that survives wind; a heavy waterproof is overkill and an umbrella is one more thing to carry through crowds. Browse on Amazon ↗

As an Amazon Associate, this site earns from qualifying purchases — we link categories, never specific products we haven't tested.

Is September worth it in Washington, D.C.?

A fair balance — decent weather, crowds you can work around.

Worth booking the marquee sights ahead for the busy days, but you can keep the rest of the trip flexible.

Compare October →

Keep planning

← Washington, D.C. in AugustThe month before — compare the crowds.Washington, D.C. in October →The month after — compare the crowds. Washington, D.C., the whole yearAll twelve months on one page. AlanyaBusy most days in September — see its full year.AmalfiBusy most days in September — see its full year.AntalyaBusy most days in September — see its full year.

Built on: United States' public holidays · the official airport-arrivals pattern (BTS T-100, measured 2023–2025; airport-arrivals proxy for visitor volume) · five years of weather records (2019–2023) · operator-confirmed events
Every figure is recomputed nightly from public and school holidays, and long-run climate normals. Gaps are shown, not filled.