Route reliability record
ORD→PHX
Chicago to Phoenix
- Flights
- 5,632
- Period
- June 2025 to May 2026
- Distance
- 1,440 mi
- Carriers
- 4
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 77.4%. The late ones land a little over an hour behind schedule. That rests on 5,632 flights, of which United Airlines flew 1,944 at 79.9% on time.
United Airlines is the most reliable of the three carriers covered here at 79.9% on time across 1,944 flights.
Key figures
On time
73.6%
Arrivals under 15 minutes late, of 5,521 completed flights
Avg delay
74 min
Across delayed arrivals only, not all flights
Cancelled
1.63%
National rate is 1.80%
Best carrier
United
79.9% on time across 1,944 flights
These figures cover 5,632 flights between June 2025 and May 2026. Beyond the headline rate, 9.1% 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 ORD to PHX
The choice of carrier is not cosmetic here. United Airlines arrives on time 79.9% of the time; Southwest Airlines manages 56.6%. Sample sizes sit next to every figure, because a two-point gap across 484 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| United Airlines | 1,944 | 79.9% | 63 min | 0.41% | B+ |
| American Airlines | 2,992 | 72.6% | 80 min | 2.21% | C |
| Frontier Airlinesthin sample | 212 | 66.0% | 79 min | 3.77% | C− |
| Southwest Airlines | 484 | 56.6% | 65 min | 2.07% | D |
The spread between United and Southwest is 23 points, wide enough that it should decide the booking. On a hundred trips that is 23 more arrivals inside the on-time window.
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 23 points, against 23 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am944 flights86.0%
- 8am–11am823 flights79.0%
- 11am–2pm1,123 flights80.7%
- 2pm–5pm1,209 flights64.8%
- 5pm–8pm672 flights66.4%
- 8pm–5am861 flights63.0%
Scale runs 55% to 90%. Rows with fewer than 30 flights show a dash.
The 8pm–5am window is where this operation falls apart: 63.0% on time, against 86.0% 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.
Across the year
When delays peak on this route
This route's year swings by 17 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 63.6% on time, 17 points below February, the best at 80.9%. 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.
Across the week, Saturday is the strongest day at 77.8% on time and Monday the weakest at 69.2%. 9 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 46% of the 107,000 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.
- 46%Late-arriving aircraft
- 34%Carrier
- 16%National Airspace System
- 4%Extreme weather
- 0%Security
46% 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 107,000 reported delay minutes here, that single category outweighs weather by 11 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 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 86.0% on time here.
Cancellations sit at 1.63% against a national 1.80%, which is ordinary. Diversions add another 0.34%.
Connections and stage length
What a delay here actually costs
For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 9.1% of arrivals land a full hour or more behind schedule, against 8.2% nationally. A 45-minute layover does not survive that, and no amount of walking quickly changes it. Ninety minutes is the honest minimum here, and two hours if the onward flight is on a separate ticket.
The 1,440 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 is a different operation and performs like one: it runs 76.8% on time across 5,633 flights, 3 points above this direction. Departure banks, aircraft rotations and the congestion at each end all differ, so scoring the two directions together would average away a real 3 points of difference.
The sample behind these figures is 5,632 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. February runs 80.9% on time and July 63.6%, a swing of 17 points. If the dates move at all, move them out of July before you think about anything else.
Common questions
ORD to PHX questions
How often is ORD to PHX 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 26.4% of the 5,632 flights in this analysis, against 22.6% nationally. Delayed flights are late by a little over an hour on average.
Which airline is most reliable on ORD to PHX?
United Airlines leads at 79.9% on time across 1,944 flights. Southwest Airlines is at the other end on 56.6%, a gap of 23 points. 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 PHX?
The 5am–8am departure window is the strongest at 86.0% on time. The 8pm–5am window is the weakest at 63.0%, 23 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 ORD to PHX?
July is the weakest month at 63.6% on time, compared with 80.9% in February. Across the year that is 17 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
- PHX to ORD — the return legseparate record
- Chicago O'Hare International (ORD) delay statistics
- Phoenix Sky Harbor International (PHX) delay statistics
- United Airlines on-time record79.9%
- American Airlines on-time record72.6%
- Frontier Airlines on-time record66.0%
- 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. ORD to PHX and PHX to ORD 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, June 2025 to May 2026. Updated monthly. How this data is collected.