Historical on-time performance
St. Louis to Boston
1,047 miData through May 2026Source: US DOT · BTS
Flights on STL–BOS arrive on time 68% of the time over the last 12 months.
On-time rate68%arrived within 15 min
p90 delay60 min1 in 10 flights is worse (tail risk)
Cancelled1.1%of scheduled flights
based on 1,279 flights over the last 12 months. On-time means arriving within 15 minutes (BTS standard).
By airline
How each carrier compares
- Republic AirwaysOn-time74%Medianon timep9045 minCancel3.3%Flights61
- Envoy AirbestOn-time73%Medianon timep9070 minCancel1.1%Flights282
- Southwest AirlinesOn-time67%Medianon timep9060 minCancel1.0%Flights936
Why flights run late
Delay causes
- Airline22%
- Weather2%
- Air traffic (NAS)30%
- Late aircraft45%
- Security1%
Most delay minutes here are attributed to Late aircraft.
When flights don't go
Why flights were cancelled
- Airline0%
- Weather79%
- Air traffic (NAS)21%
- Security0%
Most cancellations here are attributed to Weather. Shares are among 14 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 STL → 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 — 88% on time.
- Mornings88% on time · p90 15 min · 1,145 flights
- Middays76% on time · p90 40 min · 1,289 flights
- Overnights65% on time · p90 60 min · 312 flights
- Evenings63% on time · p90 70 min · 1,146 flights
- Afternoons60% on time · p90 75 min · 820 flights
Best day of week
On-time rates are fairly even by day on this route — ranging from 69% to 78% on time.
- Tuesdays78% on time · p90 40 min · 686 flights
- Saturdays76% on time · p90 40 min · 486 flights
- Wednesdays75% on time · p90 40 min · 683 flights
- Mondays71% on time · p90 55 min · 712 flights
- Fridays70% on time · p90 60 min · 716 flights
- Sundays69% on time · p90 60 min · 719 flights
- Thursdays69% on time · p90 55 min · 710 flights
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