Southwest Airlines BOS to STL on-time performance
Southwest Airlines nonstop flights from Boston to St. Louis · Aug 2025 – Jul 2026
On-time arrivals
73%
arrived < 15 min late
Cancelled
1.0%
9 flights
Avg arrival delay
18 min
60 min when late
Rank on route
#3 of 3
route average 76% on time
Key facts
- Southwest Airlines flights on BOS to STL arrived on time 73% of the time in Aug 2025 – Jul 2026.
- 1% were cancelled, and 8% arrived an hour or more late.
- That ranks #3 of 3 airlines on this route, which averaged 76% on time overall.
- The largest source of delay minutes was late-arriving aircraft (61%).
On-time trend by month
Why this airline's flights were late
- Late-arriving aircraft61%
- Airline (crew, maintenance, cleaning, fueling)22%
- Air traffic control & airport congestion12%
- Extreme weather5%
- Security0%
Other airlines on BOS to STL
- Envoy Air82% on time · 14 min avg delay
- Republic Airways79% on time · 12 min avg delay
Full BOS to STL comparison →
Southwest Airlines on-time record across all routes →
935 Southwest Airlines flights tracked on this route; 9 cancelled, 4 diverted.
Data: U.S. DOT Bureau of Transportation Statistics, Aug 2025 – Jul 2026 (12 months). Latest month published by BTS: July 2026. How we calculate this.