Historical on-time performance
Seattle to Washington
2,306 miData through Dec 2025Source: US DOT · BTS
Flights on SEA–IAD arrive on time 78% of the time over the last 12 months.
On-time rate78%arrived within 15 min
p90 delay35 min1 in 10 flights is worse (tail risk)
Cancelled0.6%of scheduled flights
based on 1,871 flights over the last 12 months. On-time means arriving within 15 minutes (BTS standard).
By airline
How each carrier compares
- United AirlinesbestOn-time83%Medianon timep9030 minCancel1.0%Flights734
- Alaska AirlinesOn-time75%Medianon timep9035 minCancel0.4%Flights831
- Delta Air LinesOn-time75%Medianon timep9045 minCancel0.3%Flights306
Why flights run late
Delay causes
- Airline42%
- Weather0%
- 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 → IAD
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 78% to 81% on time.
- Mornings81% on time · p90 30 min · 2,377 flights
- Middays80% on time · p90 25 min · 1,255 flights
- Overnights78% on time · p90 35 min · 1,941 flights
- Afternoons78% on time · p90 35 min · 879 flights
Best day of week
On-time rates are fairly even by day on this route — ranging from 76% to 84% on time.
- Wednesdays84% on time · p90 25 min · 905 flights
- Tuesdays83% on time · p90 25 min · 894 flights
- Thursdays80% on time · p90 30 min · 943 flights
- Mondays79% on time · p90 30 min · 950 flights
- Saturdays78% on time · p90 30 min · 863 flights
- Sundays77% on time · p90 40 min · 948 flights
- Fridays76% on time · p90 35 min · 949 flights
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