Alaska AirlinesAS57% on time
live
Direct flights from St Louis (STL) to Seattle (SEA): 7 nonstop departures observed each week across 1 airline. 57% of the last 7 operated flights arrived within 15 minutes of schedule. The median arrival is 14 minutes late. No cancellations were recorded across the 7 tracked flights. The nonstop covers 2,744 km, an estimated 4 hours 1 minutes in the air. Measured by Pro Flight Search from live flight boards at St Louis and Seattle. Updated 12 October 2026 at 08:31 UTC.
Today, STL → SEA
Mon 12 Oct · local timesChecked STL board 23:32 · SEA board 01:31
STL
St Louis
heavy · +42
SEA
Seattle
smooth · +0
2,744 km · ~4h 01m est.
Runs rough · 1 airline · 7x weekly · nonstop
57% on time
of the last 7 operated STL → SEA flights arrived within 15 minutes
Median arrival delay is +14 min. 0 of 7 tracked legs cancelled in the sample. Will a delayed flight be cancelled? →
Median arrival+14 minacross the last 7 operated legs
Flight time~4h 01mestimated from route distance
Weekly departures7x1 direct airline on the leg
The week
scheduled departures · origin local time06121824
Mon
Tue
Wed
Thu
Fri
Sat
Sun
Alaska Airlines
Each mark is a scheduled departure at its origin-local time, observed operating in the last 7 days. Today is highlighted.
Who flies it
observed on the boards · 7 daysHistory
operated legs · board outcomesActual board outcomes rather than schedules, paired departure and arrival per flight and day.
Full board history, day by day →
Airports right now
live boardsWeather lens
Current conditions put the pressure at STL: 40% odds of a 15+ minute delay and around +9 min expected when it bites, measured from this route's own weather-matched delay history. See live delays → · Weather risk by airport →
next sweep in 120s
How the St Louis to Seattle route actually runs
Pro Flight Search records official board updates for nonstop STL to SEA flights through the day: schedules, estimates, gate pushes and actual departures. The verdict above comes from operated flights, so it reflects what this route does rather than what the timetable promises.
Planning around a delay? Live airport delays · Weather delay risk map · Will a delayed flight be cancelled? · Do planes make up time in the air? · How we measure
Cite this data
Journalists, bloggers, and researchers may cite this page with attribution and a link to Pro Flight Search.
Suggested citation
Pro Flight Search — St Louis (STL) to Seattle (SEA) route reliability, measured from operated flights on official airport boards.
Canonical URL
How we measure this →
https://proflightsearch.com/search-flights/STL-SEA
STL to SEA questions
Is STL–SEA running on time right now?
Mostly on schedule. The departure side at STL is the weaker end, route health score 72/100. The airports section above carries the live status and delay window at both ends.
How long is the flight from STL to SEA?
Great-circle distance is 2,744 km. With typical jet cruise speed plus taxi, climb and descent, expect roughly 224–265 min gate-to-gate on this route.
How often does STL–SEA fly?
Alaska Airlines runs the route with about 14 flights a week (daily). Since one carrier owns the route, a single disruption tends to ripple through the day.
What does the route health score measure?
A blend of departure-side delay at STL and arrival-side delay at SEA, computed from rolling delay windows (refreshed every 40 minutes) with a daily-rollup fallback. Current MVFR, IFR, or LIFR endpoint weather caps the score when flight rules can limit throughput. Higher is healthier: 100 means operations are clean at both ends.
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