Route reliability record
DCA→STL
Washington to St. Louis
- Flights
- 2,415
- Period
- September 2025 to August 2026
- Distance
- 719 mi
- Carriers
- 5
This route sits in the middle of the pack with a C−. About seven flights in ten arrive on time by the DOT's definition, 5 points worse than the national rate of 77.3%. The late ones land a little over an hour behind schedule. That rests on 2,415 DCA to STL flights, of which Southwest Airlines flew 1,403 at 73.7% on time.
Best time to fly DCA to STL: a 5am–8am departure, ideally on a Wednesday. Flights in that window arrived on time 85.1% of the time and Wednesday flights 78.1%, against 71.9% for the route overall.
The national on-time rate over the same period is 77.3%, so this route runs 5 points behind the country as a whole. Across a thousand flights that is about 54 extra late arrivals.
Key figures
On time
71.9%
Arrivals under 15 minutes late, of 2,335 completed flights
Avg delay
70 min
Across delayed arrivals only, not all flights
Cancelled
3.11%
National rate is 1.89%
Best carrier
Southwest
73.7% on time across 1,403 flights
These figures cover 2,415 flights between September 2025 and August 2026. Beyond the headline rate, 10.3% 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 DCA to STL
The choice of carrier is not cosmetic here. Southwest Airlines arrives on time 73.7% of the time; PSA Airlines manages 66.7%. Sample sizes sit next to every figure, because a two-point gap across 622 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Envoy Airthin sample | 21 | 90.5% | 39 min | 0.00% | A+ |
| Republic Airwaysthin sample | 243 | 78.4% | 58 min | 4.12% | B− |
| Southwest Airlines | 1,403 | 73.7% | 61 min | 1.92% | C |
| PSA Airlines | 622 | 66.7% | 79 min | 5.63% | C− |
| American Airlinesthin sample | 126 | 62.6% | 112 min | 2.38% | D |
PSA Airlines cancels 5.6% 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 Washington to St. Louis
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. BWI → STLBaltimore to St. Louis | Southwest Airlines | 80.3% | 81.3% | 1.27% | 5am–8am, Tue | — |
| 2. DCA → STLWashington to St. Louis | Southwest Airlines | 72.3% | 73.7% | 1.92% | 8am–11am, Wed | — |
| 3. DCA → STLWashington to St. Louis | PSA Airlines | 62.9% | 66.7% | 5.63% | 8am–11am, 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 27 points, against 7 points between the best and worst carrier.
- 5am–8am80 flights85.1%
- 8am–11am536 flights84.4%
- 11am–2pm532 flights79.2%
- 2pm–5pm573 flights65.6%
- 5pm–8pm406 flights58.2%
- 8pm–5am288 flights63.2%
Scale runs 50% to 90%.
The 5pm–8pm window is where this operation falls apart: 58.2% on time, against 85.1% for the 5am–8am 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 2pm–5pm window is the busiest, with 573 flights scheduled in it.
Explore
Filter DCA to STL 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 DCA to STL, the best departure window is 5am–8am at 85.1% on time and the worst is 5pm–8pm at 58.2%, a wide gap of 26.9 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am85.1%
- 8–11am84.4%
- 11am–2pm79.2%
- 2–5pm65.6%
- 5–8pm58.2%
- 8pm–5am63.2%
best all US flightsScale 50% to 95%.
Across the year
When delays peak on this route
This route's year swings by 22 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.
July is the worst month at 59.1% on time, 22 points below September, the best at 81.3%. 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, Wednesday is the strongest day at 78.1% on time and Sunday the weakest at 64.3%, a spread of 14 points.
Delay causes
Why this route gets delayed
Late-arriving aircraft accounts for 52% of the 46,000 delay minutes carriers reported here, and the remaining four split what is left.
- 52%Late-arriving aircraft
- 31%Carrier
- 12%National Airspace System
- 5%Extreme weather
- 1%Security
52% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 46,000 reported delay minutes here, that single category outweighs weather by 11 to one. The split is drawn from 45,532 reported delay minutes.
The practical consequence: the 5am–8am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 85.1% on time here.
Cancellations run at 3.11%, 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
10.3% 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 73.7% on time across 2,417 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 2,415 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 STL after this flight
What to do with this
Booking this route
Put together: the delay figures matter less here than the 3.11% cancellation rate. A late arrival costs you a little over an hour; a cancelled flight costs you the day. Book the 5am–8am departure so there is still a schedule behind you if it goes wrong, and treat a same-day connection as optimistic. 2,335 completed flights over 12 months sit behind that.
Common questions
DCA to STL questions
How often is DCA to STL delayed?
Roughly 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 28.1% of the 2,415 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 DCA to STL?
Southwest Airlines leads at 73.7% on time across 1,403 flights. PSA Airlines is at the other end on 66.7%, a gap of 7 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 DCA to STL?
The 5am–8am departure window is the strongest at 85.1% on time. The 5pm–8pm window is the weakest at 58.2%, 27 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 July delays on DCA to STL?
July is the weakest month at 59.1% on time, compared with 81.3% in September. Across the year that is 22 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
- STL to DCA — the return legseparate record
- Ronald Reagan Washington National (DCA) delay statistics
- St. Louis Lambert International (STL) delay statistics
- Republic Airways on DCA to STL78.4%
- Southwest Airlines on DCA to STL73.7%
- PSA Airlines on DCA to STL66.7%
- American Airlines on DCA to STL62.6%
- DCA to BOS, a related route70.1%
- DEN to STL, a related route77.7%
- DCA to ORD, a related route73.8%
- Envoy Air on-time record90.5%
- Republic Airways on-time record78.4%
- Southwest Airlines on-time record73.7%
- The US routes with the most cancellations
- Why the first flight of the morning is statistically safest
Direction matters. DCA to STL and STL to DCA 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.