STL to BWI flight delays & on-time performance
Nonstop flights from St. Louis Lambert International Airport to Baltimore/Washington International Thurgood Marshall Airport · 738 miles · Aug 2025 – Jul 2026
No FAA-reported ground stops or delays at STL or BWI right now. Individual flights can still be delayed by the airline; check with your airline for your flight.
Key facts
- Flights from St. Louis (STL) to Baltimore (BWI) arrived on time 80% of the time in Aug 2025 – Jul 2026, better than the 78% national average.
- 1.3% were cancelled, and 6% arrived an hour or more late.
- Southwest Airlines is the only airline reporting nonstop flights on this route.
- Departures scheduled around 5am did best (95% on time); around 7pm did worst (60%).
- Wednesday was the most reliable day to fly (84% on time) and Sunday the least (75%).
- The largest source of delay minutes was late-arriving aircraft (57%).
Which airline is most on time from STL to BWI?
Ranked by on-time arrival rate. Regional airlines fly under their partner's brand (e.g. SkyWest for Delta Connection or United Express).
| Airline | On time | Cancelled | Avg delay | 1 hr+ late | Flights |
|---|---|---|---|---|---|
| Southwest Airlines | 80% | 1.3% | 12 min | 6.1% | 1,279 |
Best time of day to fly
On-time arrival rate by scheduled departure hour (local time).
- 5am95%196 flights
- 6am93%134 flights
- 7am94%34 flights
- 8am100%22 flights
- 9am90%131 flights
- 10am100%20 flights
- 11am88%60 flights
- 12pm85%27 flights
- 1pm73%83 flights
- 2pm81%54 flights
- 3pm57%15 flights
- 4pm70%95 flights
- 5pm68%84 flights
- 6pm71%110 flights
- 7pm60%91 flights
- 8pm62%118 flights
Best day of the week
On-time arrival rate by day of departure.
- Monday79%1.6% cancelled
- Tuesday80%0.6% cancelled
- Wednesday84%2.4% cancelled
- Thursday82%0.0% cancelled
- Friday81%0.5% cancelled
- Saturday81%0.6% cancelled
- Sunday75%3.5% cancelled
On-time trend by month
Why flights are late
Share of delay minutes by cause, as reported by airlines to the DOT.
- Late-arriving aircraft57%
- Airline (crew, maintenance, cleaning, fueling)28%
- Air traffic control & airport congestion11%
- Extreme weather4%
- Security0%
Why flights are cancelled
Share of cancellations by reason.
- Extreme weather88%
- Airline (crew, maintenance, cleaning, fueling)12%
- Air traffic control & airport congestion0%
- Security0%
STL to BWI: common questions
- How often are STL to BWI flights on time?
- 80% of flights arrived less than 15 minutes late in Aug 2025 – Jul 2026, compared with 78% for all US flights.
- How often are flights from St. Louis to Baltimore cancelled?
- 1.3% of scheduled flights were cancelled (17 of 1,279).
- How long are typical delays?
- Across all flights the average arrival delay was 12 min (early arrivals count as zero). Flights that were late arrived 58 min behind schedule on average, and 6.1% of flights were an hour or more late.
- How long is taxi time at STL?
- Flights on this route spent 11 min taxiing from the gate to takeoff on average.
Related routes
Return trip: BWI to STL — 82% on time
More flights from St. Louis
Data: U.S. DOT Bureau of Transportation Statistics, Aug 2025 – Jul 2026 (12 months). Latest month published by BTS: July 2026. Route: STL → BWI, nonstop flights by US airlines that report to the DOT. How we calculate this.