Best Time to Fly BWI to STL: On-Time Stats by Hour & Airline
Baltimore/Washington International Thurgood Marshall → St Louis Lambert International
Data through July 2026 · Last updated October 18, 2026
1,268 flights were scheduled from Baltimore (BWI) to St. Louis (STL) in the last 12 months, and 82.4% of those that flew arrived on time, 4.8 points above the US average of 77.6%.
Southwest Airlines was the only reporting airline with regular flights on this route.
February has been the best month (88% on time) and Saturday the weakest day of the week (77%).
1.1% of flights were cancelled, versus 1.8% nationally.
BWI to STL on-time performance by airline
Last 12 months. Airlines with fewer than 30 completed flights are marked “limited data”.
| Airline | On time | Avg delay when late | Cancelled | Flights |
|---|---|---|---|---|
| Southwest Airlines | 82.4% | 56 min | 1.1% | 1,268 |
80%+ good 70–79.9% fair <70% poor
Best time of day to fly BWI to STL
On-time arrival % by scheduled departure hour (local time), 2,581 flights over 24 months.
Show the numbers
| Departure hour | On time | Cancelled | Flights |
|---|---|---|---|
| 6am–7am | 94.3% | 0.3% | 337 |
| 7am–8am | 93.2% | 1.7% | 297 |
| 8am–9am | 93.5% | 0.0% | 93 |
| 9am–10am | 84.8% | 0.0% | 179 |
| 10am–11am | 91.1% | 0.8% | 126 |
| 11am–12pm | 93.8% | 1.5% | 65 |
| 12pm–1pm | 86.3% | 1.0% | 104 |
| 1pm–2pm | 87.3% | 0.0% | 63 |
| 2pm–3pm | 73.3% | 0.8% | 132 |
| 3pm–4pm | 80.6% | 0.7% | 135 |
| 4pm–5pm | 75.7% | 0.0% | 37 |
| 5pm–6pm | 73.2% | 1.6% | 125 |
| 6pm–7pm | 74.6% | 0.5% | 210 |
| 7pm–8pm | 63.9% | 2.3% | 175 |
| 8pm–9pm | 73.8% | 0.6% | 161 |
| 9pm–10pm | 63.8% | 3.1% | 191 |
| 10pm–11pm | 69.9% | 3.3% | 151 |
Best day of the week
24 months, by day of departure.
Best month to fly
24 months, by calendar month.
Holiday travel on BWI to STL
On-time arrivals during holiday periods compared with all other days, last 24 months.
| Period | On time | vs other days | Cancelled | Flights |
|---|---|---|---|---|
| Thanksgiving week (Tue before to Mon after) | 77.1% | -6.5 pts | 0.0% | 48 |
| Christmas & New Year (Dec 20 - Jan 3) | 74.2% | -9.3 pts | 2.1% | 95 |
| Summer peak (Jun 15 - Aug 15) | 73.8% | -9.7 pts | 2.2% | 505 |
| All other days | 83.5% | — | 0.9% | 1,933 |
Monthly on-time trend
On-time arrival % each month, with the 12-month US average for reference.
What causes delays on this route
Share of reported delay minutes, last 12 months (BTS cause categories).