Historical on-time performance
St. Louis to Seattle
Flights on STL–SEA arrive on time 76% of the time over the last 12 months.
based on 812 flights over the last 12 months. On-time means arriving within 15 minutes (BTS standard).
By airline
How each carrier compares
Not enough comparable data to name a most-on-time carrier — low-data carriers aren't ranked.
- Alaska AirlinesOn-time77%Medianon timep9035 minCancel1.2%Flights781
- Southwest AirlinesOn-time55%Median5 minp9045 minCancel0.0%Flights31
Why flights run late
Delay causes
- Airline29%
- Weather8%
- Air traffic (NAS)25%
- Late aircraft37%
- Security1%
Most delay minutes here are attributed to Late aircraft.
When flights don't go
Why flights were cancelled
- Airline44%
- Weather56%
- Air traffic (NAS)0%
- Security0%
Most cancellations here are attributed to Weather. Shares are among 9 cancellations with a reported cause (BTS reports causes from June 2003).
Over time
On-time trend
By season
On-time rate by month
When to fly
Best time to fly STL → SEA
All airlines · rolling 36 months (2023-06 .. 2026-05).
Best time of day
Mornings are the most reliable time of day to fly this route — 87% on time.
- Mornings87% on time · p90 15 min · 991 flights
- Afternoons80% on time · p90 25 min · 1,060 flights
- Middays74% on time · p90 30 min · 101 flights · limited
- Evenings62% on time · p90 50 min · 413 flights
Best day of week
On-time rates are fairly even by day on this route — ranging from 73% to 83% on time.
- Thursdays83% on time · p90 20 min · 389 flights
- Mondays82% on time · p90 25 min · 387 flights
- Wednesdays80% on time · p90 25 min · 329 flights
- Sundays80% on time · p90 25 min · 397 flights
- Fridays80% on time · p90 30 min · 392 flights
- Tuesdays79% on time · p90 25 min · 328 flights
- Saturdays73% on time · p90 35 min · 343 flights
Keep exploring