Route reliability record
MDW→BUF
Chicago to Buffalo
- Flights
- 829
- Period
- September 2025 to August 2026
- Distance
- 468 mi
- Carriers
- 1
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 about 55 minutes behind schedule. That rests on 829 MDW to BUF flights, with a median arrival 1 minute early.
Best time to fly MDW to BUF: a 5am–8am departure, ideally on a Tuesday. Flights in that window arrived on time 94.4% of the time and Tuesday flights 80.3%, against 74.4% 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
74.4%
Arrivals under 15 minutes late, of 816 completed flights
Avg delay
55 min
Across delayed arrivals only, not all flights
Cancelled
1.45%
National rate is 1.89%
Best carrier
Southwest
74.4% on time across 829 flights
These figures cover 829 flights between September 2025 and August 2026. On-time means an arrival less than 15 minutes after the scheduled gate time, the same threshold the Department of Transportation uses in its own reports. Cancelled and diverted flights are excluded from the on-time rate and counted separately, which is why the cancellation column matters on its own.
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Carrier by carrier
Which airline is most reliable on MDW to BUF
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 | 829 | 74.4% | 55 min | 1.45% | C |
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Best ways to make this trip
The most reliable ways to fly Chicago to Buffalo
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. 4 of the top 5 use a different airport at one end.
| Option | Airline | Success | On time | Cancelled | Best departure | Most punctual flight |
|---|---|---|---|---|---|---|
| 1. ORD → ROCChicago to Rochester | Republic Airways | 78.3% | 79.9% | 1.97% | 5am–8am, Tue | — |
| 2. ORD → ROCChicago to Rochester | Envoy Air | 76.9% | 78.9% | 2.48% | 11am–2pm, Tue | — |
| 3. ORD → BUFChicago to Buffalo | United Airlines | 74.9% | 75.7% | 1.02% | 5am–8am, Tue | — |
| 4. MDW → BUFChicago to Buffalo | Southwest Airlines | 73.3% | 74.4% | 1.45% | 5am–8am, Tue | — |
| 5. ORD → BUFChicago to Buffalo | Republic Airways | 70.9% | 74.4% | 4.67% | 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.
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 33 points, against half a point between the best and worst carrier.
- 5am–8am54 flights94.4%
- 8am–11am202 flights87.9%
- 11am–2pm203 flights75.5%
- 2pm–5pm63 flights65.1%
- 5pm–8pm258 flights61.9%
- 8pm–5am49 flights68.8%
Scale runs 55% to 100%.
The 5pm–8pm window is where this operation falls apart: 61.9% on time, against 94.4% 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 5pm–8pm window is the busiest, with 258 flights scheduled in it.
Explore
Filter MDW to BUF 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 BUF, the best departure window is 5am–8am at 94.4% on time and the worst is 5pm–8pm at 61.9%, a wide gap of 32.5 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am94.4%
- 8–11am87.9%
- 11am–2pm75.5%
- 2–5pm65.1%
- 5–8pm61.9%
- 8pm–5am68.8%
best all US flightsScale 55% to 100%.
Across the year
When delays peak on this route
This route's year swings by 24 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 62.1% on time, 24 points below April, the best at 86.6%. 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 92 flights.
Across the week, Tuesday is the strongest day at 80.3% on time and Saturday the weakest at 68.8%, a spread of 12 points.
Delay causes
Why this route gets delayed
Late-arriving aircraft accounts for 48% of the 11,000 delay minutes carriers reported here, and the remaining four split what is left.
- 48%Late-arriving aircraft
- 39%Carrier
- 11%National Airspace System
- 3%Extreme weather
48% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 11,000 reported delay minutes here, that single category outweighs weather by 16 to one. The split is drawn from 11,409 reported delay minutes.
The largest share of delay minutes, 39%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 4,418 of the 11,000 delay minutes reported here.
Cancellations sit at 1.45% against a national 1.89%, which is ordinary. Diversions add another 0.12%.
Connections and stage length
What a delay here actually costs
7.1% 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 about 55 minutes, which a normal layover absorbs.
At 468 miles this is a short hop, and stage length matters more than it looks. A flight this short spends under two hours in the air, which leaves almost nothing to claw back a late pushback with. Delay here is decided on the ground, in the turn, which is why the 5am–8am window matters as much as it does.
The return leg runs 75.2% on time across 829 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.
One caution: this is a thin sample. 829 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 BUF after this flight
What to do with this
Booking this route
Put together: treat all of this as provisional. 829 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 74.4% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 816 completed flights over 12 months sit behind that.
Common questions
MDW to BUF questions
How often is MDW to BUF 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 25.6% of the 829 flights in this analysis, against 22.7% nationally. Delayed flights are late by about 55 minutes on average.
How reliable is MDW to BUF compared with the rest of the country?
74.4% 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 MDW to BUF?
The 5am–8am departure window is the strongest at 94.4% on time. The 5pm–8pm window is the weakest at 61.9%, 33 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 BUF?
June is the weakest month at 62.1% on time, compared with 86.6% in April. Across the year that is 24 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
- BUF to MDW — the return legseparate record
- Chicago Midway International (MDW) delay statistics
- MDW to ATL, a related route78.7%
- ORD to BUF, a related route70.4%
- MDW to PHX, a related route74.7%
- Southwest Airlines on-time record74.4%
- 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 BUF and BUF 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.