PHL (Philadelphia) to SEA (Seattle) flights arrive on time 73% of the time. The most reliable airline on this route is Alaska Airlines at 74%. The average delay is 59 minutes. Delays on this route are most often caused by air traffic and busy airspace.
Source: Bureau of Transportation Statistics. Updated October 2026.PHL → SEA
PHL (Philadelphia) to SEA (Seattle)
PHL → SEA on-time performance by month
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JanFebMarAprMayJunJulAugSepOctNovDec
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This route is delayed fairly often. About 73% of flights arrive on schedule.
Delays on this route are most often caused by air traffic and busy airspace.
Accurate?
Airlines are roughly equal on this route — Alaska Airlines leads slightly at 74% vs Delta Air Lines at 72%.
Airline Comparison
Alaska Airlines leads at 74% on time; Delta Air Lines trails at 72%.
Accurate?
Good to know
Departing from PHL
77% on timeExpect ~20 min sitting on the taxiway after your gate pushes back. PHL has long runway queues.
TSA is currently ~17 min. Best time: 4 AM (about 5 min).
PHL cancels 2.1% of flights — higher than average. Have a backup plan.
Arriving at SEA
81% on timeWhen flights into SEA are late, the average delay is 58 minutes. Build buffer if you have ground plans.
If connecting at SEA: TSA is ~27 min right now. Allow at least 60 minutes for a domestic connection.
Flight cancelled or delayed?
Check what Alaska Airlines owes you — refund rights, action plan, complaint email. Free.
Flying out of PHL? 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.