IAD → SEA: cancellations & delays
Over Jan 2023 - Apr 2026, 1.0% of Washington Dulles International Airport (IAD) to Seattle–Tacoma International Airport (SEA) flights were cancelled and 20.4% arrived at least 15 minutes late, across 6,887 flights, flown by AS, UA, DL. Cancellations peak in January.
Check today's live IAD departures →Airport pages: Washington Dulles International Airport (IAD) · Seattle–Tacoma International Airport (SEA)
Rates are historical averages from U.S. DOT (BTS) on-time records; a specific flight's live estimate can differ with weather and the day's disruptions.