Historical on-time performance
Boston to St. Louis
1,046 miData through Dec 2025Source: US DOT · BTS
Flights on BOS–STL arrive on time 75% of the time over the last 12 months.
On-time rate75%arrived within 15 min
p90 delay50 min1 in 10 flights is worse (tail risk)
Cancelled0.9%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
- Southwest AirlinesOn-time72%Medianon timep9050 minCancel1.0%Flights955
- Envoy AirbestOn-time83%Medianon timep9040 minCancel0.6%Flights343
Why flights run late
Delay causes
- Airline24%
- Weather4%
- Air traffic (NAS)11%
- Late aircraft61%
- 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 BOS → STL
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 — 91% on time.
- Mornings91% on time · p90 10 min · 2,052 flights
- Middays83% on time · p90 25 min · 1,084 flights
- Afternoons64% on time · p90 70 min · 602 flights
- Evenings56% on time · p90 80 min · 902 flights
Best day of week
On-time rates are fairly even by day on this route — ranging from 73% to 82% on time.
- Saturdays82% on time · p90 25 min · 451 flights
- Tuesdays82% on time · p90 30 min · 706 flights
- Wednesdays81% on time · p90 35 min · 704 flights
- Mondays78% on time · p90 40 min · 708 flights
- Fridays78% on time · p90 40 min · 701 flights
- Thursdays77% on time · p90 40 min · 698 flights
- Sundays73% on time · p90 45 min · 696 flights
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