Historical on-time performance
Seattle to Philadelphia
2,378 miData through Dec 2025Source: US DOT · BTS
Flights on SEA–PHL arrive on time 75% of the time over the last 12 months.
On-time rate75%arrived within 15 min
p90 delay40 min1 in 10 flights is worse (tail risk)
Cancelled1.0%of scheduled flights
based on 999 flights over the last 12 months. On-time means arriving within 15 minutes (BTS standard).
By airline
How each carrier compares
Too close to call — no single carrier is clearly more on-time here.
- Alaska AirlinesOn-time74%Medianon timep9035 minCancel0.8%Flights623
- American AirlinesOn-time76%Medianon timep9040 minCancel1.3%Flights376
Why flights run late
Delay causes
- Airline40%
- Weather2%
- Air traffic (NAS)19%
- Late aircraft39%
- Security0%
Most delay minutes here are attributed to Airline.
Over time
On-time trend
By season
On-time rate by month
When to fly
Best time to fly SEA → PHL
All airlines · rolling 36 months (2023-01 .. 2025-12).
Best time of day
On-time rates are fairly even by time of day on this route — ranging from 68% to 74% on time.
- Overnights74% on time · p90 35 min · 1,768 flights
- Mornings72% on time · p90 30 min · 1,162 flights
- Middays68% on time · p90 55 min · 331 flights
Best day of week
On-time rates are fairly even by day on this route — ranging from 68% to 79% on time.
- Wednesdays79% on time · p90 25 min · 465 flights
- Tuesdays77% on time · p90 25 min · 443 flights
- Mondays73% on time · p90 35 min · 477 flights
- Saturdays72% on time · p90 30 min · 448 flights
- Thursdays72% on time · p90 35 min · 472 flights
- Fridays70% on time · p90 45 min · 479 flights
- Sundays68% on time · p90 40 min · 481 flights
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