Route reliability record

ORD→PHX

Chicago to Phoenix

Flights: 5,594
Period: July 2025 to June 2026
Distance: 1,440 mi
Carriers: 4

This route sits in the middle of the pack with a C. About seven flights in ten arrive on time by the DOT's definition, 5 points worse than the national rate of 77.6%. The late ones land a little over an hour behind schedule. That rests on 5,594 flights, of which United Airlines flew 1,938 at 79.1% on time.

United Airlines is the most reliable of the three carriers covered here at 79.1% on time across 1,938 flights.

On time

72.9%

Arrivals under 15 minutes late, of 5,479 completed flights

Avg delay

77 min

Across delayed arrivals only, not all flights

Cancelled

1.72%

National rate is 1.81%

Best carrier

United

79.1% on time across 1,938 flights

These figures cover 5,594 flights between July 2025 and June 2026. Beyond the headline rate, 10.0% 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 79.1% of the time; Southwest Airlines manages 58.3%. Sample sizes sit next to every figure, because a two-point gap across 460 flights means less than a ten-point one.

On-time performance by carrier on ORD to PHX
Airline	Flights	On time	Avg delay	Cancelled	Grade
United Airlines	1,938	79.1%	66 min	0.41%	B+
American Airlines	2,993	71.4%	84 min	2.34%	C
Frontier Airlinesthin sample	203	67.5%	82 min	3.94%	C−
Southwest Airlines	460	58.3%	67 min	2.17%	D

The spread between United and Southwest is 21 points, wide enough that it should decide the booking. On a hundred trips that is 21 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 21 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am916 flights85.3%
8am–11am826 flights78.2%
11am–2pm1,115 flights80.3%
2pm–5pm1,157 flights64.5%
5pm–8pm701 flights65.1%
8pm–5am879 flights62.5%

Scale runs 55% to 90%. Rows with fewer than 30 flights show a dash.

The 8pm–5am window is where this operation falls apart: 62.5% on time, against 85.3% 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 2pm–5pm window is the busiest, with 1,157 flights scheduled in it.

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.

Darker means more delays. Figures are on-time percentages.February best, June worst

June is the worst month at 62.3% on time, 19 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. March was the busiest month here, with 585 flights.

Across the week, Tuesday is the strongest day at 78.2% on time and Sunday the weakest at 68.0%. 10 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 49% of the 114,000 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.

Late-arriving aircraft
49%
Carrier
31%
National Airspace System
15%
Extreme weather
4%
Security
0%

49% 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 114,000 reported delay minutes here, that single category outweighs weather by 12 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 114,045 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 85.3% on time here.

Cancellations sit at 1.72% against a national 1.81%, 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. 10.0% of arrivals land a full hour or more behind schedule, against 8.1% 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 76.4% on time across 5,593 flights, 4 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 4 points of difference.

The sample behind these figures is 5,594 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 June 62.3%, a swing of 19 points. If the dates move at all, move them out of June before you think about anything else. 5,479 completed flights over 12 months sit behind that.

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 27.1% of the 5,594 flights in this analysis, against 22.4% 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 79.1% on time across 1,938 flights. Southwest Airlines is at the other end on 58.3%, a gap of 21 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 85.3% on time. The 8pm–5am window is the weakest at 62.5%, 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 June delays on ORD to PHX?

June is the weakest month at 62.3% on time, compared with 80.9% 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.

Where to go next

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, July 2025 to June 2026. Updated monthly. How this data is collected.

Key figures