Route reliability record
MDW→LAS
Chicago to Las Vegas
- Flights
- 2,236
- Period
- September 2025 to August 2026
- Distance
- 1,521 mi
- Carriers
- 2
This route lands a B+, about a point worse than the national rate of 77.3%. About one flight in four arrives 15 minutes late or worse, and those flights are late by roughly 50 minutes on average. That rests on 2,236 MDW to LAS flights, with a median arrival 2 minutes early.
Best time to fly MDW to LAS: a 5am–8am departure, ideally on a Saturday. Flights in that window arrived on time 89.1% of the time and Saturday flights 80.8%, against 76.1% for the route overall.
The US average over the same twelve months is 77.3%, 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
76.1%
Arrivals under 15 minutes late, of 2,208 completed flights
Avg delay
51 min
Across delayed arrivals only, not all flights
Cancelled
0.89%
National rate is 1.89%
Best carrier
Southwest
76.2% on time across 2,234 flights
These figures cover 2,236 flights between September 2025 and August 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.
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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 |
|---|---|---|---|---|---|
| Southwest Airlines | 2,234 | 76.2% | 51 min | 0.90% | B+ |
| Allegiant Airthin sample | 2 | 50.0% | 181 min | 0.00% | F+ |
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Best ways to make this trip
The most reliable ways to fly Chicago 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. 3 of the top 4 use a different airport at one end.
| Option | Airline | Success | On time | Cancelled | Best departure | Most punctual flight |
|---|---|---|---|---|---|---|
| 1. ORD → LASChicago to Las Vegas | United Airlines | 79.3% | 79.5% | 0.30% | 5am–8am, Sat | UA 574 07:11 |
| 2. MDW → LASChicago to Las Vegas | Southwest Airlines | 75.5% | 76.2% | 0.90% | 5am–8am, Sat (route) | — |
| 3. ORD → LASChicago to Las Vegas | Southwest Airlines | 72.9% | 73.4% | 0.73% | 5am–8am, Tue | — |
| 4. ORD → LASChicago to Las Vegas | American Airlines | 63.5% | 64.9% | 2.16% | 5am–8am, Tue | — |
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 29 points, against half a point between the best and worst carrier.
- 5am–8am460 flights89.1%
- 8am–11am520 flights86.2%
- 11am–2pm316 flights79.8%
- 2pm–5pm346 flights64.9%
- 5pm–8pm288 flights62.8%
- 8pm–5am306 flights60.4%
Scale runs 50% to 95%.
The 8pm–5am window is where this operation falls apart: 60.4% on time, against 89.1% 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 8am–11am window is the busiest, with 520 flights scheduled in it.
Explore
Filter MDW to LAS 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 MDW to LAS, the best departure window is 5am–8am at 89.1% on time and the worst is 8pm–5am at 60.4%, a wide gap of 28.7 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am89.1%
- 8–11am86.2%
- 11am–2pm79.8%
- 2–5pm64.9%
- 5–8pm62.8%
- 8pm–5am60.4%
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.
June is the worst month at 61.5% on time, 22 points below September, 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. September was the busiest month here, with 213 flights.
Across the week, Saturday is the strongest day at 80.8% on time and Friday the weakest at 72.4%, a spread of 8 points.
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 27,000 reported delay minutes.
- 40%Late-arriving aircraft
- 34%Carrier
- 22%National Airspace System
- 3%Extreme weather
- 0%Security
40% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 27,000 reported delay minutes here, that single category outweighs weather by 13 to one. The split is drawn from 27,093 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 89.1% on time here.
Cancellations are rare at 0.89%, below the national 1.89% and low enough to earn the plus on the grade. Roughly one flight in 100 is called off; the risk here is arriving late, not not arriving.
Connections and stage length
What a delay here actually costs
6.2% of arrivals land an hour or more late, close to the national 8.3%, so a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last roughly 50 minutes, 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 74.7% on time across 2,274 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 2,236 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 LAS after this flight
What to do with this
Booking this route
Put together: the calendar is the biggest lever here, not the carrier or the hour. September 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. 2,208 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 arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 23.9% of the 2,236 flights in this analysis, against 22.7% nationally. Delayed flights are late by roughly 50 minutes on average.
How reliable is MDW to LAS compared with the rest of the country?
76.1% of flights arrive on time here against a national 77.3%, a difference of about a point 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 89.1% on time. The 8pm–5am window is the weakest at 60.4%, 29 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 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
- LAS to MDW — the return legseparate record
- Chicago Midway International (MDW) delay statistics
- Harry Reid International (LAS) delay statistics
- MDW to ATL, a related route78.7%
- LAX to LAS, a related route75.8%
- MDW to PHX, a related route74.7%
- Southwest Airlines on-time record76.2%
- 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 7.05 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.
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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.