Route reliability record
MDW→LAS
Chicago to Las Vegas
- Flights
- 2,336
- Period
- July 2025 to June 2026
- Distance
- 1,521 mi
- Carriers
- 3
This route sits in the middle of the pack with a B+. Close to three flights in four arrive on time by the DOT's definition, 2 points worse than the national rate of 77.6%. The late ones land roughly 55 minutes behind schedule. That rests on 2,336 flights, with a median arrival 2 minutes early.
The US average over the same twelve months is 77.6%, 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
75.4%
Arrivals under 15 minutes late, of 2,307 completed flights
Avg delay
53 min
Across delayed arrivals only, not all flights
Cancelled
0.90%
National rate is 1.81%
Best carrier
Southwest
75.4% on time across 2,333 flights
These figures cover 2,336 flights between July 2025 and June 2026. The median arrival is 2 minutes early, which is the part an average hides: most flights here are fine, and the on-time rate is decided by a tail of badly late ones. On-time means under 15 minutes late, the DOT's own threshold.
Carrier by carrier
Which airline is most reliable on MDW to LAS
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 |
|---|---|---|---|---|---|
| Frontier Airlinesthin sample | 1 | 100.0% | — | 0.00% | A+ |
| Southwest Airlines | 2,333 | 75.4% | 53 min | 0.90% | B+ |
| Allegiant Airthin sample | 2 | 50.0% | 181 min | 0.00% | F+ |
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 31 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–8am477 flights89.3%
- 8am–11am502 flights85.7%
- 11am–2pm364 flights77.7%
- 2pm–5pm376 flights67.6%
- 5pm–8pm330 flights60.9%
- 8pm–5am287 flights57.9%
Scale runs 50% to 95%. Rows with fewer than 30 flights show a dash.
The 8pm–5am window is where this operation falls apart: 57.9% on time, against 89.3% 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 8am–11am window is the busiest, with 502 flights scheduled in it.
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.
June is the worst month at 61.5% on time, 22 points below August, the best at 83.3%. 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. July was the busiest month here, with 258 flights.
Across the week, Saturday is the strongest day at 79.5% on time and Sunday the weakest at 72.9%. 7 points is a smaller lever than departure hour, but it is free.
Delay causes
Why this route gets delayed
One category carries most of the weight here. Late-arriving aircraft accounts for 44% of the 30,000 delay minutes carriers reported, and the remaining four split what is left. The split is by minutes rather than by flights, so a few very long delays count for as much as many short ones.
- 44%Late-arriving aircraft
- 31%Carrier
- 21%National Airspace System
- 3%Extreme weather
- 0%Security
44% 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 30,000 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 30,067 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 89.3% on time here.
Cancellations sit at 0.90% against a national 1.81%, which is ordinary. Diversions add another 0.34%.
Connections and stage length
What a delay here actually costs
6.8% of arrivals land an hour or more late, close to the national 8.1%. That is the figure that decides a connection, and it says a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route are the roughly 55 minutes kind, which a normal layover absorbs.
At 1,521 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 runs 76.3% on time across 2,346 flights, within about a point 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 2,336 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.
What to do with this
Booking this route
Put together: the calendar is the biggest lever here, not the carrier or the hour. August runs 83.3% on time and June 61.5%, a swing of 22 points. If the dates move at all, move them out of June before you think about anything else. 2,307 completed flights over 12 months sit behind that.
Common questions
MDW to LAS questions
How often is MDW to LAS delayed?
About one flight in four arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 24.6% of the 2,336 flights in this analysis, against 22.4% nationally. Delayed flights are late by roughly 55 minutes on average.
How reliable is MDW to LAS compared with the rest of the country?
75.4% of flights arrive on time here against a national 77.6%, a difference of 2 points against it. That is worth a B+ on this site's grading scale.
What time of day has the fewest delays on MDW to LAS?
The 5am–8am departure window is the strongest at 89.3% on time. The 8pm–5am window is the weakest at 57.9%, 31 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 MDW to LAS?
June is the weakest month at 61.5% on time, compared with 83.3% in August. 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
- LAS to MDW — the return legseparate record
- Chicago Midway International (MDW) delay statistics
- Harry Reid International (LAS) delay statistics
- Frontier Airlines on-time record100.0%
- Southwest Airlines on-time record75.4%
- Allegiant Air on-time record50.0%
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.04 million flight records
Direction matters. MDW to LAS and LAS to MDW are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Updated monthly. How this data is collected.