St. Louis (STL) to Boston (BOS): On-Time Performance
Data through July 2026
The calendar drives reliability on STL–BOS. April 2025 flights landed on schedule 88% of the time, but October 2025 dropped to 54% — a gap of 34 points. Across the full period the route averages 73% on-time against a national 78%. Morning departures also hold up better than evening ones (86% vs 66%), which matters most in the rough months.
- On-time
- 73%
- arrived <15 min late
- Avg delay
- 18 min
- completed flights
- Cancelled
- 1.5%
- Flights/day
- 4.4
- last 12 months
- Duration
- 2h 36m
- scheduled
- Distance
- 1,047 mi
Best airline from STL to BOS
3 airlines flew this route regularly between 2024-07 and 2026-07.
| Airline | On-time | Avg delay | Cancelled | Flights |
|---|---|---|---|---|
| Republic Airwaysmost reliable | 80% | 17 min | 3.6% | 468 |
| Envoy Air | 75% | 20 min | 1.7% | 918 |
| Southwest Airlines | 71% | 18 min | 0.9% | 1,959 |
Monthly on-time trend
Best time to fly from STL to BOS
Aim for departures around 7 a.m. (92% on-time); avoid 3 p.m. departures (54%).
By day of week
| Day | On-time | Avg delay |
|---|---|---|
| Monday | 71% | 24 min |
| Tuesdaybest | 79% | 16 min |
| Wednesday | 75% | 15 min |
| Thursday | 69% | 21 min |
| Friday | 76% | 16 min |
| Saturday | 74% | 15 min |
| Sunday | 70% | 22 min |
What causes delays on this route
Share of total delay minutes by cause, as reported by carriers to the US DOT.
- Late-arriving aircraft48%
- Airline operations20%
- National airspace system28%
- Weather3%
- Security1%
Frequently asked questions
- How often are flights from STL to BOS delayed?
- 27% of STL–BOS flights arrived 15 or more minutes late (the US DOT definition of a delay) between 2024-07 and 2026-07. The average arrival delay across completed flights was 18 minutes.
- Which airline is most reliable from STL to BOS?
- Republic Airways has the best on-time record on this route at 80%, based on 468 flights. 3 airlines flew STL–BOS frequently enough to compare in this period.
- What is the best time of day to fly from STL to BOS?
- Departures around 7 a.m. have the best record (92% on-time), while departures around 3 p.m. have the worst (54%). As on most US routes, delays accumulate through the day, so earlier flights are generally safer.
- How long is the flight from STL to BOS?
- The scheduled STL–BOS flight time averages 2h 36m over 1,047 miles. Actual arrival times vary — flights on this route land 15+ minutes late 27% of the time.
- How often are STL to BOS flights cancelled?
- 1.5% of scheduled flights on this route were cancelled between 2024-07 and 2026-07, at or below the national rate of 1.6%.
- What is the worst month to fly from STL to BOS?
- October 2025 was the roughest month in this dataset, with only 54% of arrivals on time. The best was April 2025 at 88%. If your dates are flexible, that 34-point gap is worth planning around.
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Based on 3,345 flights, 2024-07–2026-07. Source: US DOT Bureau of Transportation Statistics. Updated 2026-09-28.