Route reliability record
PHL→MDW
Philadelphia to Chicago
- Flights
- 1,528
- Period
- July 2025 to June 2026
- Distance
- 668 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, 4 points worse than the national rate of 77.6%. The late ones land a little over an hour behind schedule. That rests on 1,528 PHL to MDW flights, with a median arrival 1 minute early.
Best time to fly PHL to MDW: a 5am–8am departure, ideally on a Tuesday. Flights in that window arrived on time 88.9% of the time and Tuesday flights 81.6%, against 73.2% for the route overall.
The national on-time rate over the same period is 77.6%, so this route runs 4 points behind the country as a whole. Across a thousand flights that is about 44 extra late arrivals.
Key figures
On time
73.2%
Arrivals under 15 minutes late, of 1,495 completed flights
Avg delay
69 min
Across delayed arrivals only, not all flights
Cancelled
1.57%
National rate is 1.81%
Best carrier
Southwest
72.9% on time across 1,450 flights
These figures cover 1,528 flights between July 2025 and June 2026. Beyond the headline rate, 8.8% of arrivals land a full hour or more behind schedule. That is the number that wrecks a connection, and it is not visible in an on-time percentage alone.
Carrier by carrier
Which airline is most reliable on PHL 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 | 78 | 78.9% | 119 min | 2.56% | B |
| Southwest Airlines | 1,450 | 72.9% | 67 min | 1.52% | C |
Best ways to make this trip
The most reliable ways to fly Philadelphia 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. 2 of the top 3 use a different airport at one end.
| Option | Airline | Success | On time | Cancelled | Best departure | Most punctual flight |
|---|---|---|---|---|---|---|
| 1. PHL → ORDPhiladelphia to Chicago | United Airlines | 72.7% | 74.0% | 1.75% | 5am–8am, Tue | UA 308 17:00 |
| 2. PHL → MDWPhiladelphia to Chicago | Southwest Airlines | 71.8% | 72.9% | 1.52% | 5am–8am, Tue (route) | — |
| 3. PHL → ORDPhiladelphia to Chicago | American Airlines | 70.3% | 73.2% | 3.90% | 5am–8am, Wed | — |
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 48 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–8am340 flights88.9%
- 8am–11am122 flights86.8%
- 11am–2pm396 flights80.8%
- 2pm–5pm225 flights75.8%
- 5pm–8pm380 flights50.5%
- 8pm–5am65 flights41.3%
Scale runs 35% to 95%. Rows with fewer than 30 flights show a dash.
The 8pm–5am window is where this operation falls apart: 41.3% on time, against 88.9% 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 11am–2pm window is the busiest, with 396 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 30 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.
July is the worst month at 54.7% on time, 30 points below February, the best at 84.8%. 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 159 flights.
Across the week, Tuesday is the strongest day at 81.6% on time and Sunday the weakest at 63.6%. 18 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 47% of the 28,000 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.
- 47%Late-arriving aircraft
- 25%Carrier
- 25%National Airspace System
- 3%Extreme weather
47% 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 28,000 reported delay minutes here, that single category outweighs weather by 17 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 27,573 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 88.9% on time here.
Cancellations sit at 1.57% against a national 1.81%, which is ordinary. Diversions add another 0.59%.
Connections and stage length
What a delay here actually costs
8.8% 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 last a little over an hour, which a normal layover absorbs.
The 668 miles between these two airports put this in the middle of the US network, around two and a half to three hours of block time. That is enough cruise to absorb a ten-minute late pushback and not enough to absorb thirty. It is also long enough that the aircraft usually flies three or four legs a day rather than six, which slows how fast delay compounds.
The return leg runs 75.7% on time across 1,525 flights, within 3 points 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 1,528 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. February runs 84.8% on time and July 54.7%, a swing of 30 points. If the dates move at all, move them out of July before you think about anything else. 1,495 completed flights over 12 months sit behind that.
Common questions
PHL to MDW questions
How often is PHL 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 26.8% of the 1,528 flights in this analysis, against 22.4% nationally. Delayed flights are late by a little over an hour on average.
How reliable is PHL to MDW compared with the rest of the country?
73.2% of flights arrive on time here against a national 77.6%, a difference of 4 points against it. That is worth a C on this site's grading scale.
What time of day has the fewest delays on PHL to MDW?
The 5am–8am departure window is the strongest at 88.9% on time. The 8pm–5am window is the weakest at 41.3%, 48 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 July delays on PHL to MDW?
July is the weakest month at 54.7% on time, compared with 84.8% in February. Across the year that is 30 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 PHL — the return legseparate record
- Philadelphia International (PHL) delay statistics
- Chicago Midway International (MDW) delay statistics
- PHL to ATL, a related route79.2%
- ATL to MDW, a related route76.3%
- PHL to MCO, a related route72.4%
- Frontier Airlines on-time record78.9%
- Southwest Airlines on-time record72.9%
- 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. PHL to MDW and MDW to PHL 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, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.