Carrier route record
WNDCA→LAS
Southwest Airlines · Washington to Las Vegas
- Flights
- 365
- Period
- July 2025 to June 2026
- Share of route
- 50%
- Carriers
- 2
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with Southwest Airlines.
Southwest on DCA to LAS earns an F, which is as low as this site's scale goes for a reason. Only 53.4% of flights arrive inside the 15-minute window, 24 points worse than the national rate of 77.6%. Late arrivals average about an hour. Treat any tight connection here as a coin flip. That rests on 365 flights, with a median arrival 12 minutes late.
The national on-time rate over the same period is 77.6%, so Southwest on DCA to LAS runs 24 points behind the country as a whole. Across a thousand flights that is about 242 extra late arrivals.
Key figures
On time
53.4%
Arrivals under 15 minutes late, of 358 completed flights
Avg delay
60 min
Across delayed arrivals only, not all flights
Cancelled
1.10%
National rate is 1.81%
Whole route
71.4%
Every carrier on DCA to LAS, 730 flights
These figures cover 365 flights between July 2025 and June 2026. Beyond the headline rate, 15.4% of arrivals land a full hour or more behind schedule. That is the number that wrecks a connection, and it is not visible in an on-time percentage alone.
Carrier by carrier
Southwest against every carrier on DCA to LAS
Southwest flew 365 of the 730 flights on DCA to LAS, most of the route. Its 53.4% on time is 18 points worse than the route as a whole, which runs 71.4%. Ranked by on-time rate it is last of two carriers on the route, where the range runs from American at 89.4% to Southwest at 53.4%.
Only one carrier clears this site's 365-flight floor here, so there is no comparison to draw. The table below is the full picture.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| American Airlines | 365 | 89.4% | 65 min | 1.37% | A |
| Southwest Airlines (this page) | 365 | 53.4% | 60 min | 1.10% | F |
Departure window
When Southwest runs best on this route
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 47 points, against half a point between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am39 flights92.1%
- 8am–11am—
- 11am–2pm1 flights—
- 2pm–5pm249 flights49.8%
- 5pm–8pm76 flights44.6%
- 8pm–5am—
Scale runs 35% to 100%. Rows with fewer than 30 flights show a dash.
The 5pm–8pm window is where this operation falls apart: 44.6% on time, against 92.1% 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 249 flights scheduled in it.
Across the year
Southwest on DCA to LAS through the year
June is the worst month at 33.3% on time, 47 points below March, the best at 80.0%. 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. January was the busiest month here, with 31 flights.
Across the week, Saturday is the strongest day at 86.3% on time and Thursday the weakest at 40.4%. 46 points is a smaller lever than departure hour, but it is free.
Delay causes
Why Southwest runs late on this route
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 10,000 reported delay minutes.
- 42%Late-arriving aircraft
- 30%Carrier
- 25%National Airspace System
- 4%Extreme weather
- 0%Security
42% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. That is a cascade, and cascades start small and grow through the day. Across 10,000 reported delay minutes here, that single category outweighs weather by 11 to one. It is the strongest argument for booking the first departure of the morning, when the aircraft has been sitting at the gate overnight with nothing to inherit. The split is drawn from 10,075 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 92.1% on time here.
Cancellations sit at 1.10% against a national 1.81%, which is ordinary. Diversions add another 0.82%.
Connections and stage length
What a delay here costs
For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 15.4% of arrivals land a full hour or more behind schedule, against 8.1% nationally. A 45-minute layover does not survive that, and no amount of walking quickly changes it. Ninety minutes is the honest minimum here, and two hours if the onward flight is on a separate ticket.
At 2,089 miles this is transcontinental flying, and long routes get a quiet structural advantage. Scheduled block time on a flight this length carries more padding in absolute minutes, so a twenty-minute late departure often still becomes an on-time arrival. Read the on-time rate here as slightly flattering next to a short-haul route with the same operational quality.
The return leg is a different operation and performs like one: it runs 71.8% on time across 365 flights, 18 points above this direction. Departure banks, aircraft rotations and the congestion at each end all differ, so scoring the two directions together would average away a real 18 points of difference.
One caution: this is a thin sample. 365 flights over twelve months is enough to clear this site's floor but not enough to pin the rate down tightly, and a single bad week moves it by more than a point. Treat the grade as a rough reading.
What to do with this
Booking Southwest on DCA to LAS
Put together: treat all of this as provisional. 365 flights over twelve months is enough to clear this site's floor and not enough to be confident to better than a couple of points. The 53.4% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 358 completed flights over 12 months sit behind that.
Related
Where to go next
- DCA to LAS, every carrier
- Southwest on LAS to DCA, the return leg
- American Airlines on DCA to LAS89.4%
- Southwest Airlines network-wide record
- Ronald Reagan Washington National (DCA) delay statistics
- Harry Reid International (LAS) delay statistics
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.04 million flight records
Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.