Route reliability record
LAS→MDW
Las Vegas to Chicago
- Flights
- 2,274
- Period
- September 2025 to August 2026
- Distance
- 1,521 mi
- Carriers
- 2
This route sits in the middle of the pack with a C+. Close to three flights in four arrive on time by the DOT's definition, 3 points worse than the national rate of 77.3%. The late ones land roughly 45 minutes behind schedule. That rests on 2,274 LAS to MDW flights, with a median arrival 2 minutes early.
Best time to fly LAS to MDW: a 5am–8am departure, ideally on a Tuesday. Flights in that window arrived on time 94.8% of the time and Tuesday flights 80.9%, against 74.7% 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
74.7%
Arrivals under 15 minutes late, of 2,244 completed flights
Avg delay
46 min
Across delayed arrivals only, not all flights
Cancelled
0.62%
National rate is 1.89%
Best carrier
Southwest
74.7% on time across 2,272 flights
These figures cover 2,274 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 LAS to MDW
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 | 2,272 | 74.7% | 46 min | 0.62% | C+ |
| Allegiant Airthin sample | 2 | 50.0% | 147 min | 0.00% | F+ |
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Best ways to make this trip
The most reliable ways to fly Las Vegas to Chicago
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. LAS → ORDLas Vegas to Chicago | United Airlines | 77.9% | 78.2% | 0.34% | 8pm–5am, Tue | UA 2102 23:59 |
| 2. LAS → MDWLas Vegas to Chicago | Southwest Airlines | 74.2% | 74.7% | 0.62% | 5am–8am, Tue (route) | — |
| 3. LAS → ORDLas Vegas to Chicago | American Airlines | 73.6% | 75.2% | 2.16% | 5am–8am, Tue | AA 2258 07:00 |
| 4. LAS → ORDLas Vegas to Chicago | Southwest Airlines | 67.0% | 67.1% | 0.18% | 8am–11am, 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 44 points, against half a point between the best and worst carrier.
- 5am–8am472 flights94.8%
- 8am–11am332 flights80.6%
- 11am–2pm410 flights68.1%
- 2pm–5pm392 flights64.2%
- 5pm–8pm269 flights51.3%
- 8pm–5am399 flights78.9%
Scale runs 45% to 100%.
The 5pm–8pm window is where this operation falls apart: 51.3% on time, against 94.8% 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 5am–8am window is the busiest, with 472 flights scheduled in it.
Explore
Filter LAS to MDW 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 LAS to MDW, the best departure window is 5am–8am at 94.8% on time and the worst is 5pm–8pm at 51.3%, a wide gap of 43.5 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am94.8%
- 8–11am80.6%
- 11am–2pm68.1%
- 2–5pm64.2%
- 5–8pm51.3%
- 8pm–5am78.9%
best all US flightsScale 45% to 100%.
Across the year
When delays peak on this route
This route's year swings by 19 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 64.0% on time, 19 points below September, the best at 82.9%. 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. September was the busiest month here, with 212 flights.
Across the week, Tuesday is the strongest day at 80.9% on time and Friday the weakest at 68.4%, a spread of 13 points.
Delay causes
Why this route gets delayed
Late-arriving aircraft accounts for 43% of the 26,000 delay minutes carriers reported here, and the remaining four split what is left.
- 43%Late-arriving aircraft
- 42%Carrier
- 14%National Airspace System
- 1%Extreme weather
- 0%Security
43% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 26,000 reported delay minutes here, that single category outweighs weather by 43 to one. The split is drawn from 26,203 reported delay minutes.
The largest share of delay minutes, 42%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 11,000 of the 26,000 delay minutes reported here.
Cancellations are rare at 0.62%, 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
5.9% 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 45 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 76.1% on time across 2,236 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 2,274 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 MDW 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 82.9% on time and June 64.0%, a swing of 19 points. If the dates move at all, move them out of June before you think about anything else. 2,244 completed flights over 12 months sit behind that.
Common questions
LAS to MDW questions
How often is LAS to MDW 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 25.3% of the 2,274 flights in this analysis, against 22.7% nationally. Delayed flights are late by roughly 45 minutes on average.
How reliable is LAS to MDW compared with the rest of the country?
74.7% of flights arrive on time here against a national 77.3%, a difference of 3 points against it. That is worth a C+ on this site's grading scale.
What time of day has the fewest delays on LAS to MDW?
The 5am–8am departure window is the strongest at 94.8% on time. The 5pm–8pm window is the weakest at 51.3%, 44 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 LAS to MDW?
June is the weakest month at 64.0% on time, compared with 82.9% in September. Across the year that is 19 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
- MDW to LAS — the return legseparate record
- Harry Reid International (LAS) delay statistics
- Chicago Midway International (MDW) delay statistics
- LAS to LAX, a related route77.9%
- ATL to MDW, a related route75.2%
- LAS to DEN, a related route76.5%
- Southwest Airlines on-time record74.7%
- 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. LAS to MDW and MDW to LAS 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.