Historical on-time performance
Washington to Boston
413 miData through May 2026Source: US DOT · BTS
Flights on IAD–BOS arrive on time 74% of the time over the last 12 months.
On-time rate74%arrived within 15 min
p90 delay60 min1 in 10 flights is worse (tail risk)
Cancelled1.7%of scheduled flights
based on 1,484 flights over the last 12 months. On-time means arriving within 15 minutes (BTS standard).
By airline
How each carrier compares
- United AirlinesOn-time74%Medianon timep9060 minCancel1.7%Flights1,484
Why flights run late
Delay causes
- Airline19%
- Weather7%
- Air traffic (NAS)51%
- Late aircraft23%
- Security0%
Most delay minutes here are attributed to Air traffic (NAS).
When flights don't go
Why flights were cancelled
- Airline0%
- Weather80%
- Air traffic (NAS)20%
- Security0%
Most cancellations here are attributed to Weather. Shares are among 25 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 IAD → 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 — 90% on time.
- Mornings90% on time · p90 10 min · 1,074 flights
- Middays80% on time · p90 40 min · 1,096 flights
- Overnights76% on time · p90 45 min · 1,088 flights
- Evenings61% on time · p90 95 min · 1,096 flights
- Afternoons54% on time · p90 70 min · 120 flights · limited
Best day of week
On-time rates are fairly even by day on this route — ranging from 72% to 82% on time.
- Saturdays82% on time · p90 35 min · 636 flights
- Tuesdays80% on time · p90 45 min · 630 flights
- Wednesdays78% on time · p90 40 min · 632 flights
- Fridays75% on time · p90 65 min · 649 flights
- Mondays73% on time · p90 55 min · 642 flights
- Thursdays73% on time · p90 65 min · 641 flights
- Sundays72% on time · p90 60 min · 644 flights
Keep exploring