Carrier route record
WNDCA→LAS
Southwest Airlines · Washington to Las Vegas
- Flights
- 365
- Period
- September 2025 to August 2026
- Share of route
- 50%
- Carriers
- 2
Historical statistics for September 2025 to August 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 49.4% of flights arrive inside the 15-minute window, 28 points worse than the national rate of 77.3%. Late arrivals average about an hour. Treat any tight connection here as a coin flip. That rests on 365 flights, with a median arrival 16 minutes late.
The national on-time rate over the same period is 77.3%, so Southwest on DCA to LAS runs 28 points behind the country as a whole. Across a thousand flights that is about 279 extra late arrivals.
Key figures
On time
49.4%
Arrivals under 15 minutes late, of 356 completed flights
Avg delay
62 min
Across delayed arrivals only, not all flights
Cancelled
1.64%
National rate is 1.89%
Whole route
69.2%
Every carrier on DCA to LAS, 729 flights
These figures cover 365 flights between September 2025 and August 2026. Beyond the headline rate, 18.5% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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Carrier by carrier
Southwest against every carrier on DCA to LAS
Southwest flew 365 of the 729 flights on DCA to LAS, most of the route. Its 49.4% on time is 20 points worse than the route as a whole, which runs 69.2%. Ranked by on-time rate it is last of two carriers on the route, where the range runs from American at 88.8% to Southwest at 49.4%. One of those carriers flew fewer than 365 flights here, so treat their positions as rough.
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 Airlinesthin sample | 364 | 88.8% | 72 min | 1.37% | A |
| Southwest Airlines (this page) | 365 | 49.4% | 62 min | 1.64% | F |
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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 46 points, against half a point between the best and worst carrier.
- 5am–8am39 flights86.8%
- 8am–11am—
- 11am–2pm1 flights—
- 2pm–5pm268 flights45.6%
- 5pm–8pm57 flights41.1%
- 8pm–5am—
Scale runs 35% to 90%. Rows with fewer than 30 flights show a dash.
The 5pm–8pm window is where this operation falls apart: 41.1% on time, against 86.8% 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 268 flights scheduled in it.
Across the year
Southwest on DCA to LAS through the year
July 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 82.4% on time and Monday the weakest at 35.8%, a spread of 47 points.
Arrival by arrival
How late Southwest on DCA to LAS runs when it is late
The 180 late arrivals split 60 under half an hour, 54 between 30 and 60 minutes, and 66 an hour or more.
- 15+ min early39 flights11.0%
- Within 15 min137 flights38.5%
- 15–29 min late60 flights16.9%
- 30–59 min late54 flights15.2%
- 1–2 hours late44 flights12.4%
- 2+ hours late22 flights6.2%
Scale runs 0% to 100%.
Share of 356 completed flights by arrival against schedule.
49 of 208 late departures made up the time and arrived on time, 24% of them. In the other direction, 21 flights left on time yet arrived 15 minutes late or more, so that delay built up after pushback: in the air, in a holding pattern or on the ground at LAS.
The worst days
Worst days for Southwest on DCA to LAS
The latest arrival of the period was on 10 August 2026, 6 hours behind schedule; most of its delay minutes were filed as a late-arriving aircraft. On three of the five worst days the largest share was filed as carrier-caused (crew, maintenance, fuelling, baggage).
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 10 August 2026 | 6 hours | Late-arriving aircraft |
| 12 June 2026 | 5 hours 5 minutes | Carrier |
| 29 November 2025 | 4 hours 19 minutes | Carrier |
| 30 September 2025 | 3 hours 59 minutes | Carrier |
| 10 June 2026 | 3 hours 6 minutes | Late-arriving aircraft |
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 11,000 reported delay minutes.
- 42%Late-arriving aircraft
- 33%Carrier
- 22%National Airspace System
- 3%Extreme weather
- 1%Security
42% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 11,000 reported delay minutes here, that single category outweighs weather by 16 to one. The split is drawn from 11,091 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 86.8% on time here.
Cancellations sit at 1.64% against a national 1.89%, which is ordinary. Diversions add another 0.82%.
Connections and stage length
What a delay here costs
18.5% 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.
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 69.7% on time across 364 flights, 20 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 20 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 49.4% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 356 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 LAS88.8%
- 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 7.05 million flight records
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.