Historical on-time performance
St. Louis to Boston
1,047 miData through Dec 2025Source: US DOT · BTS
Flights on STL–BOS arrive on time 72% of the time over the last 12 months.
On-time rate72%arrived within 15 min
p90 delay60 min1 in 10 flights is worse (tail risk)
Cancelled0.8%of scheduled flights
based on 1,298 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.
- Southwest AirlinesOn-time71%Medianon timep9060 minCancel0.8%Flights955
- Envoy AirOn-time75%Medianon timep9060 minCancel0.6%Flights343
Why flights run late
Delay causes
- Airline20%
- Weather3%
- Air traffic (NAS)33%
- Late aircraft43%
- Security0%
Most delay minutes here are attributed to Late aircraft.
Over time
On-time trend
By season
On-time rate by month
When to fly
Best time to fly STL → BOS
All airlines · rolling 36 months (2023-01 .. 2025-12).
Best time of day
Mornings are the most reliable time of day to fly this route — 89% on time.
- Mornings89% on time · p90 15 min · 1,316 flights
- Middays76% on time · p90 40 min · 1,105 flights
- Overnights66% on time · p90 60 min · 331 flights
- Evenings65% on time · p90 60 min · 1,014 flights
- Afternoons63% on time · p90 70 min · 883 flights
Best day of week
On-time rates are fairly even by day on this route — ranging from 71% to 80% on time.
- Tuesdays80% on time · p90 40 min · 697 flights
- Wednesdays76% on time · p90 35 min · 694 flights
- Saturdays76% on time · p90 35 min · 450 flights
- Mondays74% on time · p90 45 min · 709 flights
- Thursdays71% on time · p90 55 min · 699 flights
- Sundays71% on time · p90 55 min · 696 flights
- Fridays71% on time · p90 55 min · 704 flights
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