SEA (Seattle) to PHL (Philadelphia) flights arrive on time 77% of the time. The most reliable airline on this route is Delta Air Lines at 84%. The average delay is 58 minutes. Delays on this route are most often caused by the incoming plane arriving late.
Source: Bureau of Transportation Statistics. Updated October 2026.SEA → PHL
SEA (Seattle) to PHL (Philadelphia)
SEA → PHL on-time performance by month
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This route is on time most of the time. About 77% of flights arrive on schedule.
Delays on this route are most often caused by the incoming plane arriving late.
Accurate?
Delta Air Lines edges out Alaska Airlines on this route — 84% vs 77% on time.
Airline Comparison
Delta Air Lines leads at 84% on time; Alaska Airlines trails at 77%.
Accurate?
Good to know
Departing from SEA
81% on timeExpect ~20 min sitting on the taxiway after your gate pushes back. SEA has long runway queues.
TSA is currently ~5 min. Best time: 4 AM (about 5 min).
Arriving at PHL
77% on timeWhen flights into PHL are late, the average delay is 84 minutes. Build buffer if you have ground plans.
If connecting at PHL: TSA is ~5 min right now. Allow at least 60 minutes for a domestic connection.
PHL has a 2.1% cancellation rate — keep the airline app handy for rebooking.
Flight cancelled or delayed?
Check what Delta Air Lines owes you — refund rights, action plan, complaint email. Free.
Flying out of SEA? We'll brief you.
Delays, TSA, weather, gates — we'll let you know if something matters.
Know someone flying soon?
Send them the link — delay data, TSA waits, weather, all free.
Data last updated October 2026. Source: Bureau of Transportation Statistics.