SEA (Seattle) to IAD (Washington) flights arrive on time 81% of the time. The most reliable airline on this route is United Airlines at 87%. The average delay is 58 minutes. Delays on this route are most often caused by the airline (crew, maintenance, or boarding).
Source: Bureau of Transportation Statistics. Updated March 2026.SEA → IAD
SEA (Seattle) to IAD (Washington)
SEA → IAD on-time performance by month
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This route is on time most of the time. About 81% of flights arrive on schedule.
Delays on this route are most often caused by the airline (crew, maintenance, or boarding).
Accurate?
United Airlines edges out Alaska Airlines on this route — 87% vs 77% on time.
Airline Comparison
United Airlines leads at 87% on time; Alaska Airlines trails at 77%.
Accurate?
Good to know
Departing from SEA
82% on timeExpect ~19 min sitting on the taxiway after your gate pushes back. SEA has long runway queues.
TSA is currently ~10 min. Best time: 4 AM (about 5 min).
Arriving at IAD
83% on timeWhen flights into IAD are late, the average delay is 74 minutes. Build buffer if you have ground plans.
If connecting at IAD: TSA is ~5 min right now. Allow at least 60 minutes for a domestic connection.
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Data last updated March 2026. Source: Bureau of Transportation Statistics.