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DelayAtlas

Route reliability record

DCALAS

Washington to Las Vegas

Flights
730
Period
July 2025 to June 2026
Distance
2,089 mi
Carriers
2
CGRADE

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, 6 points worse than the national rate of 77.6%. The late ones land about an hour behind schedule. That rests on 730 DCA to LAS flights, of which American Airlines flew 365 at 89.4% on time.

Best time to fly DCA to LAS: a 5am–8am departure, ideally on a Saturday. Flights in that window arrived on time 90.6% of the time and Saturday flights 87.4%, against 71.4% for the route overall.

The national on-time rate over the same period is 77.6%, so this route runs 6 points behind the country as a whole. Across a thousand flights that is about 62 extra late arrivals.

Key figures

On time

71.4%

Arrivals under 15 minutes late, of 718 completed flights

Avg delay

61 min

Across delayed arrivals only, not all flights

Cancelled

1.23%

National rate is 1.81%

Best carrier

American

89.4% on time across 365 flights

These figures cover 730 flights between July 2025 and June 2026. Beyond the headline rate, 9.3% 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

Which airline is most reliable on DCA to LAS

The choice of carrier is not cosmetic here. American Airlines arrives on time 89.4% of the time; Southwest Airlines manages 53.4%. Sample sizes sit next to every figure, because a two-point gap across 365 flights means less than a ten-point one.

On-time performance by carrier on DCA to LAS
AirlineFlightsOn timeAvg delayCancelledGrade
American Airlines36589.4%65 min1.37%A
Southwest Airlines36553.4%60 min1.10%F

The spread between American and Southwest is 36 points, wide enough that it should decide the booking. On a hundred trips that is 36 more arrivals inside the on-time window.

Best ways to make this trip

The most reliable ways to fly Washington to Las Vegas

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. 2 of the top 4 use a different airport at one end.

Most reliable ways to fly from DCA to LAS
OptionAirlineSuccessOn timeCancelledBest departureMost punctual flight
1. DCALASWashington to Las VegasAmerican Airlines88.2%89.4%1.37%5am–8am, Sun
2. IADLASWashington to Las VegasUnited Airlines86.4%86.8%0.50%8am–11am, Wed (route)UA 1323 09:00
3. BWILASBaltimore to Las VegasSouthwest Airlines77.2%78.1%1.10%5am–8am, Tue
4. DCALASWashington to Las VegasSouthwest Airlines52.8%53.4%1.10%5am–8am, Sat

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.

Plan this trip by month, day and time

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 46 points, against 36 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

  • 5am–8am239 flights90.6%
  • 8am–11am165 flights88.5%
  • 11am–2pm1 flights
  • 2pm–5pm249 flights49.8%
  • 5pm–8pm76 flights44.6%
  • 8pm–5am

Scale runs 35% to 95%. Rows with fewer than 30 flights show a dash.

The 5pm–8pm window is where this operation falls apart: 44.6% on time, against 90.6% 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

When delays peak on this route

This route's year swings by 27 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.

On-time rate by calendar month72J73F87M72A77M60J73J69A67S71O70N68D
Darker means more delays. Figures are on-time percentages.March best, June worst

June is the worst month at 60.0% on time, 27 points below March, the best at 86.9%. 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 62 flights.

Across the week, Saturday is the strongest day at 87.4% on time and Thursday the weakest at 65.4%. 22 points is a smaller lever than departure hour, but it is free.

On-time rate by day of the week67.0Mon73.8Tue70.6Wed65.4Thu67.6Fri87.4Sat68.3Sun
Monday: 67.0 percent on time. Tuesday: 73.8 percent on time. Wednesday: 70.6 percent on time. Thursday: 65.4 percent on time. Friday: 67.6 percent on time. Saturday: 87.4 percent on time. Sunday: 68.3 percent on time

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 13,000 reported delay minutes.

  • Late-arriving aircraft
    40%
  • Carrier
    33%
  • National Airspace System
    24%
  • Extreme weather
    3%
  • Security
    0%

40% 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 13,000 reported delay minutes here, that single category outweighs weather by 13 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 12,561 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 90.6% on time here.

Cancellations sit at 1.23% against a national 1.81%, which is ordinary. Diversions add another 0.41%.

Connections and stage length

What a delay here actually costs

For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 9.3% 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 75.5% on time across 730 flights, 4 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 4 points of difference.

One caution: this is a thin sample. 730 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.

Work out the risk of missing a connection in LAS after this flight

What to do with this

Booking this route

Put together: treat all of this as provisional. 730 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 71.4% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 718 completed flights over 12 months sit behind that.

Common questions

DCA to LAS questions

How often is DCA to LAS delayed?

Roughly one flight in three arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 28.6% of the 730 flights in this analysis, against 22.4% nationally. Delayed flights are late by about an hour on average.

Which airline is most reliable on DCA to LAS?

American Airlines leads at 89.4% on time across 365 flights. Southwest Airlines is at the other end on 53.4%, a gap of 36 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 LAS?

The 5am–8am departure window is the strongest at 90.6% on time. The 5pm–8pm window is the weakest at 44.6%, 46 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 DCA to LAS?

June is the weakest month at 60.0% on time, compared with 86.9% in March. Across the year that is 27 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

Direction matters. DCA to LAS and LAS 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, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.