Historical on-time performance
Philadelphia to Seattle
2,378 miData through May 2026Source: US DOT · BTS
Flights on PHL–SEA arrive on time 65% of the time over the last 12 months.
On-time rate65%arrived within 15 min
p90 delay55 min1 in 10 flights is worse (tail risk)
Cancelled1.6%of scheduled flights
based on 1,161 flights over the last 12 months. On-time means arriving within 15 minutes (BTS standard).
By airline
How each carrier compares
- American AirlinesbestOn-time70%Medianon timep9040 minCancel1.9%Flights533
- Alaska AirlinesOn-time61%Medianon timep9065 minCancel1.4%Flights628
Why flights run late
Delay causes
- Airline27%
- Weather4%
- Air traffic (NAS)37%
- Late aircraft31%
- Security0%
Most delay minutes here are attributed to Air traffic (NAS).
When flights don't go
Why flights were cancelled
- Airline26%
- Weather74%
- Air traffic (NAS)0%
- Security0%
Most cancellations here are attributed to Weather. Shares are among 19 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 PHL → 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 — 80% on time.
- Mornings80% on time · p90 30 min · 1,272 flights
- Evenings63% on time · p90 55 min · 2,084 flights
Best day of week
On-time rates are fairly even by day on this route — ranging from 66% to 75% on time.
- Tuesdays75% on time · p90 40 min · 463 flights
- Saturdays72% on time · p90 45 min · 470 flights
- Wednesdays70% on time · p90 40 min · 466 flights
- Thursdays68% on time · p90 50 min · 493 flights
- Mondays68% on time · p90 50 min · 492 flights
- Sundays68% on time · p90 50 min · 496 flights
- Fridays66% on time · p90 55 min · 497 flights
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