Washington (DCA) to Seattle (SEA): On-Time Performance
Data through July 2026
Washington (DCA) to Seattle (SEA) effectively runs on two schedules. In September 2024, 92% of arrivals were on time; in December 2025 that fell to 45% — a 47-point seasonal swing. Across the full period the route averages 77% on-time against a national 78%.
- On-time
- 77%
- arrived <15 min late
- Avg delay
- 18 min
- completed flights
- Cancelled
- 1.5%
- Flights/day
- 3.0
- last 12 months
- Duration
- 5h 58m
- scheduled
- Distance
- 2,329 mi
Best airline from DCA to SEA
2 airlines flew this route regularly between 2024-07 and 2026-07.
| Airline | On-time | Avg delay | Cancelled | Flights |
|---|---|---|---|---|
| Alaska Airlinesmost reliable | 79% | 13 min | 1.1% | 1,519 |
| Delta Air Lines | 71% | 33 min | 2.6% | 509 |
Monthly on-time trend
Best time to fly from DCA to SEA
Aim for departures around 8 a.m. (83% on-time); avoid 4 p.m. departures (71%).
By day of week
| Day | On-time | Avg delay |
|---|---|---|
| Monday | 78% | 16 min |
| Tuesday | 79% | 19 min |
| Wednesday | 72% | 20 min |
| Thursday | 71% | 26 min |
| Friday | 78% | 15 min |
| Saturdaybest | 85% | 10 min |
| Sunday | 76% | 20 min |
What causes delays on this route
Share of total delay minutes by cause, as reported by carriers to the US DOT.
- Late-arriving aircraft27%
- Airline operations26%
- National airspace system36%
- Weather11%
Frequently asked questions
- How often are flights from DCA to SEA delayed?
- 23% of DCA–SEA flights arrived 15 or more minutes late (the US DOT definition of a delay) between 2024-07 and 2026-07. The average arrival delay across completed flights was 18 minutes.
- Which airline is most reliable from DCA to SEA?
- Alaska Airlines has the best on-time record on this route at 79%, based on 1,519 flights. 2 airlines flew DCA–SEA frequently enough to compare in this period.
- What is the best time of day to fly from DCA to SEA?
- Departures around 8 a.m. have the best record (83% on-time), while departures around 4 p.m. have the worst (71%). As on most US routes, delays accumulate through the day, so earlier flights are generally safer.
- How long is the flight from DCA to SEA?
- The scheduled DCA–SEA flight time averages 5h 58m over 2,329 miles. Actual arrival times vary — flights on this route land 15+ minutes late 23% of the time.
- How often are DCA to SEA flights cancelled?
- 1.5% of scheduled flights on this route were cancelled between 2024-07 and 2026-07, at or below the national rate of 1.6%.
- What is the worst month to fly from DCA to SEA?
- December 2025 was the roughest month in this dataset, with only 45% of arrivals on time. The best was September 2024 at 92%. If your dates are flexible, that 47-point gap is worth planning around.
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Based on 2,028 flights, 2024-07–2026-07. Source: US DOT Bureau of Transportation Statistics. Updated 2026-09-28.