SEA to DCA flight delays
Seattle, WA (SEA) Washington, VA (DCA) · 2,329 miles
1,094 flights · January 2025 – August 2026 · US Bureau of Transportation Statistics
81.64%
Arrived on time
Within 15 minutes of schedule
1.74%
Cancelled
Share of scheduled flights
68 min
When late, late by
Average across delayed arrivals
13 min
Delay per flight
Averaged over every flight flown
What the record says about this route
Which airline you fly changes the odds here. Delta Air Lines arrived on time 15.6 points more often than Alaska Airlines over the same period on the same route — same airports, same weather, same air traffic control. A gap that survives all of that is about how the two airlines are run.
The season swings this route hard. In May it ran 27.4 points more punctual than in September — a difference bigger than the one between the best and worst airlines on most routes. If the date is flexible, it is worth more than the carrier.
The route has been getting better. The later months in the record run 8.9 points more punctual than the earlier ones, which usually means a schedule that was too tight has been given more room.
The two directions do not behave alike. DCA to SEA arrives on time 8.4 points less often than the outbound. Delay accumulates through the flying day, so whichever direction is scheduled later tends to carry the worse record — which is an argument for booking the morning departure if the choice exists.
Which airline should you fly on this route?
Over January 2025 – August 2026, Delta Air Lines arrived on time most often on SEA to DCA. Alaska Airlines was late most often. Flights ran closest to schedule in May and worst in September.
Every airline on SEA to DCA
Ranked by how many flights each one operated. A carrier with fewer than 100 flights in the period is listed but not graded.
| Airline | Flights | On time | Cancelled | Avg delay | Grade |
|---|---|---|---|---|---|
| Alaska Airlines | 729 | 76.45% | 1.1% | 58 min | C |
| Delta Air Lines | 365 | 92.07% | 3.01% | 126 min | A |
Month by month
Share of flights that arrived within 15 minutes of schedule, by month flown.
The return leg
DCA to SEA Washington back to Seattle 73.2% on time DOther routes from Seattle
Common questions
Are flights from Seattle to Washington usually delayed?
81.64% of flights on the SEA to DCA route arrived within 15 minutes of schedule, so roughly 2 in every ten arrived late. That is better than the average route in this record.
Which airline is most on time from Seattle to Washington?
Delta Air Lines, at 92.07% on time across 365 flights. The least punctual on the route was Alaska Airlines at 76.45%.
How often are SEA to DCA flights cancelled?
1.74% of scheduled flights did not operate — about 17 in every thousand. That is in the normal range.
What is the best month to fly Seattle to Washington?
May, when 91.4% of flights arrived on time. The worst was September at 64%.
When SEA to DCA flights are late, how late are they?
About 68 minutes on average across the flights that arrived more than 15 minutes behind schedule.
What these figures do and do not tell you
Everything on this page is counted from the flights that actually operated on SEA to DCA during January 2025 – August 2026, as reported by the airlines to the US Bureau of Transportation Statistics. "On time" is the federal definition: arriving at the gate within 15 minutes of the scheduled time.
A route's record is a description of the past, not a forecast. Weather, air traffic control and the aircraft's earlier flights that day drive most delays, and none of them are predictable from a historical rate. What the record does tell you is whether this route runs late more often than others, and which carrier on it has the better history — which is the part you can actually act on when you book.
Cancellations are counted separately from delays because they are a different problem for a traveller: a late flight still gets you there. How the grade is calculated →