Historical on-time performance
Seattle to Boston
2,496 miData through May 2026Source: US DOT · BTS
Flights on SEA–BOS arrive on time 74% of the time over the last 12 months.
On-time rate74%arrived within 15 min
p90 delay45 min1 in 10 flights is worse (tail risk)
Cancelled1.2%of scheduled flights
based on 2,393 flights over the last 12 months. On-time means arriving within 15 minutes (BTS standard).
By airline
How each carrier compares
- Delta Air LinesbestOn-time80%Medianon timep9030 minCancel1.5%Flights978
- Alaska AirlinesOn-time71%Medianon timep9045 minCancel1.0%Flights1,210
- JetBlue AirwaysOn-time55%Median5 minp90110 minCancel0.5%Flights205
Why flights run late
Delay causes
- Airline38%
- Weather6%
- Air traffic (NAS)32%
- Late aircraft24%
- Security0%
Most delay minutes here are attributed to Airline.
When flights don't go
Why flights were cancelled
- Airline46%
- Weather50%
- Air traffic (NAS)4%
- Security0%
Most cancellations here are attributed to Weather. Shares are among 28 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 SEA → BOS
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 — 82% on time.
- Mornings82% on time · p90 25 min · 2,210 flights
- Overnights75% on time · p90 40 min · 2,626 flights
- Afternoons75% on time · p90 40 min · 1,712 flights
- Middays53% on time · p90 90 min · 997 flights
Best day of week
On-time rates are fairly even by day on this route — ranging from 71% to 78% on time.
- Tuesdays78% on time · p90 35 min · 1,033 flights
- Wednesdays78% on time · p90 40 min · 1,056 flights
- Saturdays75% on time · p90 40 min · 984 flights
- Mondays74% on time · p90 45 min · 1,113 flights
- Fridays72% on time · p90 45 min · 1,126 flights
- Thursdays72% on time · p90 50 min · 1,121 flights
- Sundays71% on time · p90 45 min · 1,112 flights
Keep exploring