71% of flights from St. Louis to Washington arrived on time over the past 12 months. That is worse than the typical U.S. route. The 8 a.m. departures ran on time 87% of the time; the 5 p.m. ones 52%. Most reliable airline: Southwest Airlines (71%). 13% 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 STL → DCA: when a flight was late, it was under 45 minutes late 55% of the time. About 1 in 12 flights landed an hour or more late, and 1 in 59 three hours or more; 3.2% were cancelled outright.
- On time or early71%
- 15–30 min late9.0%
- 30–60 min late7.6%
- 1–2 hours late5.5%
- 2–3 hours late1.3%
- 3+ hours late1.7%
- Diverted1.1%
- Cancelled3.2%
Share of all 2,417 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 | 1,404 | 71% | 1.5% | −2 min | 8.0% | +57 min | Southwest Airlines |
| American Airlines | 1,013 | 70% | 5.5% | −9 min | 9.3% | +102 min | PSA Airlines 61%, Republic Airways 24%, American Airlines 13%, Envoy 2% |
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 STL). Delays build through the day as late planes knock on, so early flights usually do best.
By airline and hour
| Departs | Southwest Airlines | American Airlines |
|---|---|---|
| 6 a.m. | — | 81% |
| 8 a.m. | 87% | — |
| 9 a.m. | — | 76% |
| 10 a.m. | — | 78% |
| 1 p.m. | 67% | — |
| 3 p.m. | 66% | — |
| 5 p.m. | — | 50% |
| 7 p.m. | 58% | — |
Last flight of the day
On STL → DCA, each airline's last flight of the day was cancelled 5.1% of the time, against 2.4% for its earlier flights (2.2× as often). It arrived 3+ hours late 2.2% of the time (earlier flights: 1.5%). 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 |
|---|---|---|---|---|---|
| American Airlines | 5:02 p.m. | 9.7% | 3.5% | 3.7% | first flight 6:00 a.m. |
| Southwest Airlines | 7:55 p.m. | 1.1% | 1.1% | 1.5% | first flight 8:30 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 DCA tonight, book an earlier flight so there's a backup if it's cancelled.
By month
Each calendar month pooled over 2023–2026. Best: October (83%). Worst: July (62%).
By day of week
| Day | Flights | On time | Cancelled |
|---|---|---|---|
| Monday | 382 | 66% | 3.9% |
| Tuesday | 377 | 75% | 3.5% |
| Wednesday | 376 | 79% | 1.6% |
| Thursday | 371 | 66% | 2.2% |
| Friday | 371 | 69% | 4.0% |
| Saturday | 219 | 78% | 2.3% |
| Sunday | 321 | 62% | 4.7% |
Why flights were late
Share of delay minutes on flights 15+ minutes late, as reported to BTS by the airlines.
Cancellations: weather 53 · air traffic/airport 18 · airline 6
Month by month
Worst days in the past year
| Date | Flights | On time | Cancelled |
|---|---|---|---|
| Dec 5, 2025 | 8 | 0% | 2 |
| Jan 25, 2026 | 7 | 0% | 7 |
| Aug 7, 2026 | 7 | 0% | 4 |
| Mar 16, 2026 | 7 | 0% | 3 |
| Jan 26, 2026 | 7 | 0% | 3 |
Nearby airport alternatives
Other ways to make the same trip, using airports within 60 miles of St. Louis or Washington. STL → BWI has been 7 points more reliable.
| Route | Flights | On time | Cancelled |
|---|---|---|---|
| STL → DCA (this route) | 2,417 | 71% | 3.2% |
| STL → BWI St. Louis Lambert to Baltimore/Washington | 1,271 | 78% | 1.3% |
| STL → IAD St. Louis Lambert to Washington Dulles | 717 | 76% | 0.8% |
Questions
How often are flights from STL to DCA on time?
71% of 2,417 scheduled flights from St. Louis, MO to Washington, DC arrived within 15 minutes of schedule between September 2025 and August 2026. 3.2% were cancelled.
What is the best time of day to fly STL to DCA?
Flights scheduled to leave at 8 a.m. were the most reliable (87% on time). The 5 p.m. departures were the least (52%).
Which airline is most on time from STL to DCA?
Southwest Airlines: 71% of its 1,404 flights on the route arrived on time. American Airlines: 70%.
What month has the most delays from STL to DCA?
July (62% on time). The best month is October (83%), over 2023–2026.
Is the last flight of the day from STL to DCA more likely to be cancelled?
Yes. Each airline's last STL–DCA flight of the day was cancelled 5.1% of the time over the past year, against 2.4% for its earlier flights. If the last flight is cancelled, the next one is usually the following morning.
Related
- DCA → STL (return)
- St. Louis Lambert (STL) delays by hour
- Flights into Washington Reagan National (DCA)
- Southwest Airlines on-time record
- American 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.