80% of flights from Baltimore to St. Louis arrived on time over the past 12 months. That is about the typical U.S. route. The 6 a.m. departures ran on time 93% of the time; the 9 p.m. ones 62%. 7% of flights arrived more than an hour late or not at all.
How late?
The on-time rate treats a flight 20 minutes late the same as one 5 hours late. Here's the split for BWI → STL: when a flight was late, it was under 45 minutes late 62% of the time. About 1 in 19 flights landed an hour or more late, and 1 in 105 three hours or more; 1.3% were cancelled outright.
- On time or early80%
- 15–30 min late8.2%
- 30–60 min late4.8%
- 1–2 hours late3.3%
- 2–3 hours late1.2%
- 3+ hours late1.0%
- Diverted0.2%
- Cancelled1.3%
Share of all 1,260 scheduled flights, past 12 months, by arrival time against schedule.
By airline
| Airline | Flights | On time | Cancelled | Typical arrival | 1h+ late | Avg when late | Operated by |
|---|---|---|---|---|---|---|---|
| Southwest Airlines | 1,260 | 80% | 1.3% | −6 min | 5.4% | +56 min | Southwest Airlines |
Airline = the name on the ticket. Regional flights (e.g. "Delta Connection") count under the ticketing airline, and the operator is listed.
Best time of day to fly
On-time rate by scheduled departure hour (local time at BWI). Delays build through the day as late planes knock on, so early flights usually do best.
Last flight of the day
On BWI → STL, each airline's last flight of the day was cancelled 2.2% of the time, against 0.9% for its earlier flights (2.5× as often). It arrived 3+ hours late 2.2% of the time (earlier flights: 0.4%). It matters more than the numbers suggest. Miss an earlier flight and there's another one that evening; miss the last one and you're usually waiting until morning.
| Airline | Last departure | Last: cancelled | Last: 3h+ late | Earlier: cancelled | Next morning |
|---|---|---|---|---|---|
| Southwest Airlines | 8:45 p.m. | 2.2% | 2.2% | 0.9% | first flight 6:30 a.m. |
Last flight = the airline's last scheduled departure on this route that day, on days it flies the route at least twice; past 12 months. Times are typical scheduled times over the latest three months.
If you need to be in STL tonight, book an earlier flight so there's a backup if it's cancelled.
By month
Each calendar month pooled over 2023–2026. Best: February (89%). Worst: July (67%).
By day of week
| Day | Flights | On time | Cancelled |
|---|---|---|---|
| Monday | 196 | 79% | 1.5% |
| Tuesday | 161 | 88% | 0.6% |
| Wednesday | 160 | 81% | 0.0% |
| Thursday | 190 | 81% | 2.1% |
| Friday | 193 | 82% | 1.0% |
| Saturday | 164 | 79% | 0.0% |
| Sunday | 196 | 72% | 3.1% |
Why flights were late
Share of delay minutes on flights 15+ minutes late, as reported to BTS by the airlines.
Cancellations: weather 9 · airline 5 · air traffic/airport 2
Month by month
Worst days in the past year
| Date | Flights | On time | Cancelled |
|---|---|---|---|
| Jul 28, 2026 | 3 | 0% | 0 |
| Jan 25, 2026 | 3 | 0% | 3 |
| Mar 28, 2026 | 3 | 0% | 0 |
| Oct 10, 2025 | 3 | 0% | 0 |
| Nov 29, 2025 | 5 | 20% | 0 |
Nearby airport alternatives
Other ways to make the same trip, using airports within 60 miles of Baltimore or St. Louis. None has been clearly more reliable than BWI → STL.
| Route | Flights | On time | Cancelled |
|---|---|---|---|
| BWI → STL (this route) | 1,260 | 80% | 1.3% |
| IAD → STL Washington Dulles to St. Louis Lambert | 720 | 76% | 1.1% |
| DCA → STL Washington Reagan National to St. Louis Lambert | 2,415 | 70% | 3.1% |
Questions
How often are flights from BWI to STL on time?
80% of 1,260 scheduled flights from Baltimore, MD to St. Louis, MO arrived within 15 minutes of schedule between September 2025 and August 2026. 1.3% were cancelled.
What is the best time of day to fly BWI to STL?
Flights scheduled to leave at 6 a.m. were the most reliable (93% on time). The 9 p.m. departures were the least (62%).
What month has the most delays from BWI to STL?
July (67% on time). The best month is February (89%), over 2023–2026.
Is the last flight of the day from BWI to STL more likely to be cancelled?
Yes. Each airline's last BWI–STL flight of the day was cancelled 2.2% of the time over the past year, against 0.9% for its earlier flights. If the last flight is cancelled, the next one is usually the following morning.
Related
- STL → BWI (return)
- Baltimore/Washington (BWI) delays by hour
- Flights into St. Louis Lambert (STL)
- Southwest Airlines on-time record
- Connecting off this flight? Check the risk
Domestic flights by the airlines that report to the U.S. DOT, plus their regional partners. "On time" means arriving less than 15 minutes after schedule; cancelled and diverted flights count as not on time. Past performance is a guide, not a forecast. Method.