Route reliability record
LAS→MDW
Las Vegas to Chicago
- Flights
- 2,346
- Period
- July 2025 to June 2026
- Distance
- 1,521 mi
- Carriers
- 3
This route lands a B+, about a point worse than the national rate of 77.6%. About one flight in four arrive 15 minutes late or worse, and those flights are late by roughly 50 minutes on average. That is a workable record, not a spotless one. That rests on 2,346 flights, with a median arrival 3 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
76.3%
Arrivals under 15 minutes late, of 2,310 completed flights
Avg delay
49 min
Across delayed arrivals only, not all flights
Cancelled
0.85%
National rate is 1.81%
Best carrier
Southwest
76.3% on time across 2,343 flights
These figures cover 2,346 flights between July 2025 and June 2026. The median arrival is 3 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 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 |
|---|---|---|---|---|---|
| Frontier Airlinesthin sample | 1 | 100.0% | — | 0.00% | A+ |
| Southwest Airlines | 2,343 | 76.3% | 49 min | 0.85% | B+ |
| Allegiant Airthin sample | 2 | 50.0% | 147 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 39 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–8am499 flights94.3%
- 8am–11am346 flights79.1%
- 11am–2pm419 flights73.1%
- 2pm–5pm404 flights64.6%
- 5pm–8pm293 flights55.7%
- 8pm–5am385 flights81.6%
Scale runs 45% to 100%. Rows with fewer than 30 flights show a dash.
The 5pm–8pm window is where this operation falls apart: 55.7% on time, against 94.3% 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 5am–8am window is the busiest, with 499 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 20 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, 20 points below August, the best at 84.4%. 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 255 flights.
Across the week, Saturday is the strongest day at 81.9% on time and Thursday the weakest at 69.3%. 13 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 45% of the 27,000 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.
- 45%Late-arriving aircraft
- 43%Carrier
- 12%National Airspace System
- 1%Extreme weather
- 0%Security
45% 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 27,000 reported delay minutes here, that single category outweighs weather by 45 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 26,759 reported delay minutes.
The largest share of delay minutes, 43%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. Unlike weather, that is a management outcome, and it is the category where the gap between two carriers on the same schedule is genuinely earned. It accounts for 11,000 of the 27,000 delay minutes reported here.
Cancellations are rare at 0.85%, below the national 1.81% 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
5.2% 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 50 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 75.4% on time across 2,336 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 2,346 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 84.4% on time and June 64.0%, a swing of 20 points. If the dates move at all, move them out of June before you think about anything else. 2,310 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 arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 23.7% of the 2,346 flights in this analysis, against 22.4% nationally. Delayed flights are late by roughly 50 minutes on average.
How reliable is LAS to MDW compared with the rest of the country?
76.3% of flights arrive on time here against a national 77.6%, 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 LAS to MDW?
The 5am–8am departure window is the strongest at 94.3% on time. The 5pm–8pm window is the weakest at 55.7%, 39 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 84.4% in August. Across the year that is 20 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
- Frontier Airlines on-time record100.0%
- Southwest Airlines on-time record76.3%
- 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. 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.
Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Updated monthly. How this data is collected.