Route reliability record
ORD→PHL
Chicago to Philadelphia
- Flights
- 5,082
- Period
- September 2025 to August 2026
- Distance
- 678 mi
- Carriers
- 4
This route carries a cancellation problem, not just a delay problem: 3.4% of scheduled flights never operate, against 1.9% nationally. Of the ones that do fly, about seven flights in ten arrive on time, worth a C− overall. The punctuality figure counts only flights that actually departed, so it flatters an operation that cancels this often. That rests on 5,082 ORD to PHL flights, of which American Airlines flew 3,010 at 71.2% on time.
Best time to fly ORD to PHL: a 5am–8am departure, ideally on a Tuesday. Flights in that window arrived on time 86.4% of the time and Tuesday flights 77.2%, against 70.8% for the route overall.
The national on-time rate over the same period is 77.3%, so this route runs 7 points behind the country as a whole. Across a thousand flights that is about 65 extra late arrivals.
Key figures
On time
70.8%
Arrivals under 15 minutes late, of 4,905 completed flights
Avg delay
92 min
Across delayed arrivals only, not all flights
Cancelled
3.38%
National rate is 1.89%
Best carrier
American
71.2% on time across 3,010 flights
These figures cover 5,082 flights between September 2025 and August 2026. Beyond the headline rate, 13.3% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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Carrier by carrier
Which airline is most reliable on ORD to PHL
The two carriers here are closely matched: half a point separate the best from the worst. At that spread, schedule and price are better tie-breakers than reliability. Sample sizes are shown so you can see which rows are worth weighing.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Republic Airwaysthin sample | 27 | 81.5% | 46 min | 0.00% | B+ |
| American Airlines | 3,010 | 71.2% | 95 min | 4.42% | C− |
| United Airlines | 1,849 | 71.2% | 81 min | 1.57% | C |
| Frontier Airlinesthin sample | 196 | 60.8% | 133 min | 5.10% | D− |
American Airlines cancels 4.4% of what it schedules here, the highest in the table. A cancelled flight never appears in an on-time rate, so read that column alongside the punctuality one rather than after it.
Flight by flight
Flights on ORD to PHL
The flight numbers below flew this route at least 250 times in the period, busiest first. Each has its own record, with its schedule and delay causes.
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Best ways to make this trip
The most reliable ways to fly Chicago to Philadelphia
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. 1 of the top 3 use a different airport at one end.
| Option | Airline | Success | On time | Cancelled | Best departure | Most punctual flight |
|---|---|---|---|---|---|---|
| 1. MDW → PHLChicago to Philadelphia | Southwest Airlines | 73.4% | 74.7% | 1.78% | 5am–8am, Tue (route) | — |
| 2. ORD → PHLChicago to Philadelphia | United Airlines | 70.1% | 71.2% | 1.57% | 5am–8am, Tue | UA 2182 11:05 |
| 3. ORD → PHLChicago to Philadelphia | American Airlines | 68.1% | 71.2% | 4.42% | 5am–8am, Tue | AA 2840 14:50 |
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–8am822 flights86.4%
- 8am–11am765 flights78.0%
- 11am–2pm903 flights74.0%
- 2pm–5pm945 flights66.0%
- 5pm–8pm953 flights57.9%
- 8pm–5am694 flights64.2%
Scale runs 50% to 90%.
The 5pm–8pm window is where this operation falls apart: 57.9% on time, against 86.4% 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 953 flights scheduled in it.
Explore
Filter ORD to PHL 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 ORD to PHL, the best departure window is 5am–8am at 86.4% on time and the worst is 5pm–8pm at 57.9%, a wide gap of 28.5 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am86.4%
- 8–11am78.0%
- 11am–2pm74.0%
- 2–5pm66.0%
- 5–8pm57.9%
- 8pm–5am64.2%
best all US flightsScale 50% to 95%.
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.
August is the worst month at 61.1% on time, 19 points below February, the best at 80.5%. 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. August was the busiest month here, with 512 flights.
Across the week, Tuesday is the strongest day at 77.2% on time and Monday the weakest at 66.2%, a spread of 11 points.
Delay causes
Why this route gets delayed
Late-arriving aircraft accounts for 51% of the 131,000 delay minutes carriers reported here, and the remaining four split what is left.
- 51%Late-arriving aircraft
- 25%Carrier
- 18%National Airspace System
- 5%Extreme weather
- 0%Security
51% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 131,000 reported delay minutes here, that single category outweighs weather by 10 to one. The split is drawn from 131,440 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 86.4% on time here.
Cancellations run at 3.38%, against 1.89% nationally. That is about one flight in 30 cancelled outright. A cancelled flight is invisible in every on-time figure on this page, so the punctuality numbers above describe only the flights that actually operated.
Connections and stage length
What a delay here actually costs
13.3% of arrivals land a full hour or more behind schedule, against 8.3% nationally. Ninety minutes is the honest minimum for a connection here, and two hours if the onward flight is on a separate ticket.
The 678 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.
The return leg runs 73.1% on time across 5,075 flights, within 2 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 5,082 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 PHL after this flight
What to do with this
Booking this route
Put together: the delay figures matter less here than the 3.38% cancellation rate. A late arrival costs you an hour and a half; a cancelled flight costs you the day. Book the 5am–8am departure so there is still a schedule behind you if it goes wrong, and treat a same-day connection as optimistic. 4,905 completed flights over 12 months sit behind that.
Common questions
ORD to PHL questions
How often is ORD to PHL delayed?
Roughly one flight in three arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 29.2% of the 5,082 flights in this analysis, against 22.7% nationally. Delayed flights are late by an hour and a half on average.
Which airline is most reliable on ORD to PHL?
American Airlines leads at 71.2% on time across 3,010 flights. United Airlines is at the other end on 71.2%, a gap of half a point. Sample size matters as much as the percentage: a rate built from a few hundred flights moves around far more than one built from ten thousand.
What time of day has the fewest delays on ORD to PHL?
The 5am–8am departure window is the strongest at 86.4% on time. The 5pm–8pm window is the weakest at 57.9%, 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 August delays on ORD to PHL?
August is the weakest month at 61.1% on time, compared with 80.5% in February. 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
- PHL to ORD — the return legseparate record
- Chicago O'Hare International (ORD) delay statistics
- Philadelphia International (PHL) delay statistics
- American Airlines on ORD to PHL71.2%
- United Airlines on ORD to PHL71.2%
- Frontier Airlines on ORD to PHL60.8%
- ORD to LGA, a related route66.6%
- ATL to PHL, a related route74.6%
- ORD to BOS, a related route66.6%
- Republic Airways on-time record81.5%
- American Airlines on-time record71.2%
- United Airlines on-time record71.2%
- The US routes with the most cancellations
- Why the first flight of the morning is statistically safest
Direction matters. ORD to PHL and PHL to ORD 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.