SEA (Seattle) to DEN (Denver) flights arrive on time 79% of the time. The most reliable airline on this route is United Airlines at 88%. The average delay is 60 minutes. Delays on this route are most often caused by the incoming plane arriving late.
Source: Bureau of Transportation Statistics. Updated July 2026.SEA → DEN
SEA (Seattle) to DEN (Denver)
SEA → DEN on-time performance by month
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JanFebMarAprMayJunJulAugSepOctNovDec
Worse
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This route is on time most of the time. About 79% of flights arrive on schedule.
Delays on this route are most often caused by the incoming plane arriving late.
Accurate?
United Airlines edges out Frontier Airlines on this route — 88% vs 74% on time.
Airline Comparison
United Airlines leads at 88% on time; Frontier Airlines trails at 74%.
Accurate?
Good to know
Departing from SEA
80% on timeExpect ~21 min sitting on the taxiway after your gate pushes back. SEA has long runway queues.
TSA is currently ~18 min. Best time: 4 AM (about 5 min).
Arriving at DEN
79% on timeWhen flights into DEN are late, the average delay is 69 minutes. Build buffer if you have ground plans.
If connecting at DEN: TSA is ~14 min right now. Allow at least 60 minutes for a domestic connection.
Flight cancelled or delayed?
Check what United Airlines 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 July 2026. Source: Bureau of Transportation Statistics.