Route reliability record
STL→DCA
St. Louis to Washington
- Flights
- 2,417
- Period
- September 2025 to August 2026
- Distance
- 719 mi
- Carriers
- 5
This route sits in the middle of the pack with a C−. Close to three flights in four arrive on time by the DOT's definition, 4 points worse than the national rate of 77.3%. The late ones land a little over an hour behind schedule. That rests on 2,417 STL to DCA flights, of which PSA Airlines flew 621 at 74.5% on time.
Best time to fly STL to DCA: a 8am–11am departure, ideally on a Saturday. Flights in that window arrived on time 86.2% of the time and Saturday flights 80.3%, against 73.7% for the route overall.
The US average over the same twelve months is 77.3%, so there is little to separate this route from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
73.7%
Arrivals under 15 minutes late, of 2,314 completed flights
Avg delay
74 min
Across delayed arrivals only, not all flights
Cancelled
3.19%
National rate is 1.89%
Best carrier
PSA
74.5% on time across 621 flights
These figures cover 2,417 flights between September 2025 and August 2026. Beyond the headline rate, 9.0% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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Carrier by carrier
Which airline is most reliable on STL to DCA
The two carriers here are closely matched: 2 points separate the best from the worst. At that spread, schedule and price are better tie-breakers than reliability. Sample sizes are shown so you can see which rows are worth weighing.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| American Airlinesthin sample | 128 | 77.4% | 91 min | 3.12% | B− |
| Republic Airwaysthin sample | 242 | 76.1% | 81 min | 4.96% | B− |
| PSA Airlines | 621 | 74.5% | 115 min | 6.44% | C− |
| Southwest Airlines | 1,404 | 72.7% | 57 min | 1.50% | C |
| Envoy Airthin sample | 22 | 72.7% | 32 min | 0.00% | C+ |
PSA Airlines cancels 6.4% of what it schedules here, the highest in the table. A cancelled flight never appears in an on-time rate, so read that column alongside the punctuality one rather than after it.
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Best ways to make this trip
The most reliable ways to fly St. Louis to Washington
Every airline on this route and on the routes between nearby airports, ranked by how often a scheduled flight actually operated and arrived on time. 1 of the top 3 use a different airport at one end.
| Option | Airline | Success | On time | Cancelled | Best departure | Most punctual flight |
|---|---|---|---|---|---|---|
| 1. STL → BWISt. Louis to Baltimore | Southwest Airlines | 78.3% | 79.3% | 1.26% | 5am–8am, Wed | — |
| 2. STL → DCASt. Louis to Washington | Southwest Airlines | 71.6% | 72.7% | 1.50% | 8am–11am, Wed | — |
| 3. STL → DCASt. Louis to Washington | PSA Airlines | 69.7% | 74.5% | 6.44% | 5am–8am, Wed | — |
Success is the share of scheduled flights that operated and arrived less than 15 minutes late, so a cancelled flight counts against it. “(route)” means the best time comes from every carrier on the route rather than this airline alone.
Departure window
The best time of day to leave
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 35 points, against 2 points between the best and worst carrier.
- 5am–8am340 flights83.7%
- 8am–11am600 flights86.2%
- 11am–2pm444 flights71.7%
- 2pm–5pm470 flights67.2%
- 5pm–8pm441 flights63.8%
- 8pm–5am122 flights51.7%
Scale runs 45% to 90%.
The 8pm–5am window is where this operation falls apart: 51.7% on time, against 86.2% for the 8am–11am slot. By evening the aircraft flying these rotations have absorbed a full day of small delays and there is no slack left to recover in. The 8am–11am window is the busiest, with 600 flights scheduled in it.
Explore
Filter STL to DCA by airline, time, month and day
Pick a breakdown and a carrier. The dashed mark on each row is the same slice for every US flight.
On STL to DCA, the best departure window is 8am–11am at 86.2% on time and the worst is 8pm–5am at 51.7%, a wide gap of 34.5 points. All US flights leaving 8am–11am ran 83.9%.
- 5–8am83.7%
- 8–11am86.2%
- 11am–2pm71.7%
- 2–5pm67.2%
- 5–8pm63.8%
- 8pm–5am51.7%
best all US flightsScale 45% to 95%.
Across the year
When delays peak on this route
This route's year swings by 17 points from best month to worst, which is wide. An annual average tells you very little about the week you are actually flying, so read the strip rather than the headline if your dates are fixed.
June is the worst month at 64.6% on time, 17 points below April, the best at 81.8%. Summer afternoon convection and peak-season schedules land on the same weeks every year, so this is a pattern you can book around rather than a run of bad luck. October was the busiest month here, with 223 flights.
Across the week, Saturday is the strongest day at 80.3% on time and Sunday the weakest at 66.7%, a spread of 14 points.
Delay causes
Why this route gets delayed
Carriers report a reason for every delay minute they cause, in five DOT categories. The split below is by minutes, not by number of flights, so a handful of very long weather delays weighs as much as many short ones. It covers 45,000 reported delay minutes.
- 37%Late-arriving aircraft
- 36%Carrier
- 24%National Airspace System
- 3%Extreme weather
- 1%Security
37% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 45,000 reported delay minutes here, that single category outweighs weather by 13 to one. The split is drawn from 44,943 reported delay minutes.
The largest share of delay minutes, 36%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 16,000 of the 45,000 delay minutes reported here.
Cancellations run at 3.19%, against 1.89% nationally. That is about one flight in 30 cancelled outright. A cancelled flight is invisible in every on-time figure on this page, so the punctuality numbers above describe only the flights that actually operated.
Connections and stage length
What a delay here actually costs
9.0% of arrivals land a full hour or more behind schedule, against 8.3% nationally. Ninety minutes is the honest minimum for a connection here, and two hours if the onward flight is on a separate ticket.
The 719 miles between these two airports put this in the middle of the US network, around two and a half to three hours of block time. That is enough cruise to absorb a ten-minute late pushback and not enough to absorb thirty.
The return leg runs 71.9% on time across 2,415 flights, within 2 points of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.
The sample behind these figures is 2,417 flights, enough that the headline rate is stable to within roughly a point. The hour-block and month splits divide that further, so read the thinner bars with more caution than the headline.
Work out the risk of missing a connection in DCA after this flight
What to do with this
Booking this route
Put together: the delay figures matter less here than the 3.19% cancellation rate. A late arrival costs you a little over an hour; a cancelled flight costs you the day. Book the 8am–11am departure so there is still a schedule behind you if it goes wrong, and treat a same-day connection as optimistic. 2,314 completed flights over 12 months sit behind that.
Common questions
STL to DCA questions
How often is STL to DCA delayed?
About one flight in four arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 26.3% of the 2,417 flights in this analysis, against 22.7% nationally. Delayed flights are late by a little over an hour on average.
Which airline is most reliable on STL to DCA?
PSA Airlines leads at 74.5% on time across 621 flights. Southwest Airlines is at the other end on 72.7%, a gap of 2 points. Sample size matters as much as the percentage: a rate built from a few hundred flights moves around far more than one built from ten thousand.
What time of day has the fewest delays on STL to DCA?
The 8am–11am departure window is the strongest at 86.2% on time. The 8pm–5am window is the weakest at 51.7%, 35 points behind. Later departures inherit delays from earlier flights the same aircraft has already flown, which is why the curve slopes the way it does.
How bad are June delays on STL to DCA?
June is the weakest month at 64.6% on time, compared with 81.8% in April. Across the year that is 17 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.
Related
Where to go next
- DCA to STL — the return legseparate record
- St. Louis Lambert International (STL) delay statistics
- Ronald Reagan Washington National (DCA) delay statistics
- American Airlines on STL to DCA77.4%
- Republic Airways on STL to DCA76.1%
- PSA Airlines on STL to DCA74.5%
- Southwest Airlines on STL to DCA72.7%
- STL to DEN, a related route75.0%
- BOS to DCA, a related route72.6%
- STL to ATL, a related route84.6%
- American Airlines on-time record77.4%
- Republic Airways on-time record76.1%
- PSA Airlines on-time record74.5%
- The US routes with the most cancellations
- Why the first flight of the morning is statistically safest
Direction matters. STL to DCA and DCA to STL are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
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Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.