Route reliability record
IAH→PHX
Houston to Phoenix
- Flights
- 2,930
- Period
- July 2025 to June 2026
- Distance
- 1,009 mi
- Carriers
- 5
This route lands a B+, about a point better than the national rate of 77.6%. About one flight in five arrive 15 minutes late or worse, and those flights are late by an hour and a half on average. That is a workable record, not a spotless one. That rests on 2,930 flights, of which American Airlines flew 622 at 81.6% on time.
The US average over the same twelve months is 77.6%, 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
78.7%
Arrivals under 15 minutes late, of 2,903 completed flights
Avg delay
86 min
Across delayed arrivals only, not all flights
Cancelled
0.82%
National rate is 1.81%
Best carrier
American
81.6% on time across 622 flights
These figures cover 2,930 flights between July 2025 and June 2026. Beyond the headline rate, 8.4% 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 IAH to PHX
The two carriers here are closely matched: 2 points 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 |
|---|---|---|---|---|---|
| Envoy Airthin sample | 67 | 83.3% | 98 min | 1.49% | B |
| American Airlines | 622 | 81.6% | 168 min | 1.45% | B |
| United Airlines | 1,784 | 80.0% | 64 min | 0.34% | B+ |
| SkyWest Airlinesthin sample | 180 | 69.7% | 76 min | 2.78% | C |
| Frontier Airlinesthin sample | 277 | 68.5% | 74 min | 1.08% | C |
No carrier stands out. American tops the table at 81.6%, 2 points clear of the bottom, which is inside the range this kind of sample moves year to year.
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 27 points, against 2 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am182 flights94.5%
- 8am–11am751 flights83.1%
- 11am–2pm248 flights79.3%
- 2pm–5pm896 flights80.1%
- 5pm–8pm375 flights72.8%
- 8pm–5am478 flights67.3%
Scale runs 60% to 100%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 94.5% of the time, against 67.3% for the overnight window. That is 27 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 2pm–5pm window is the busiest, with 896 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 23 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 67.9% on time, 23 points below February, the best at 90.9%. 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 302 flights.
Across the week, Tuesday is the strongest day at 83.7% on time and Sunday the weakest at 73.2%. 11 points is a smaller lever than departure hour, but it is free.
Delay causes
Why this route gets delayed
Carriers report a reason for every delay minute they cause, in five DOT categories. The split below is by minutes, not by number of flights, so a handful of very long weather delays weighs as much as many short ones. It covers 53,000 reported delay minutes.
- 39%Late-arriving aircraft
- 38%Carrier
- 15%National Airspace System
- 9%Extreme weather
39% 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 53,000 reported delay minutes here, that single category outweighs weather by 5 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 53,005 reported delay minutes.
The largest share of delay minutes, 38%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. Unlike weather, that is a management outcome, and it is the category where the gap between two carriers on the same schedule is genuinely earned. It accounts for 20,000 of the 53,000 delay minutes reported here.
Cancellations are rare at 0.82%, below the national 1.81% and low enough to earn the plus on the grade. Roughly one flight in 100 is called off; the risk here is arriving late, not not arriving.
Connections and stage length
What a delay here actually costs
8.4% 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 are the an hour and a half kind, which a normal layover absorbs.
The 1,009 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 81.3% on time across 2,927 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 2,930 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 90.9% on time and June 67.9%, a swing of 23 points. If the dates move at all, move them out of June before you think about anything else. 2,903 completed flights over 12 months sit behind that.
Common questions
IAH to PHX questions
How often is IAH to PHX delayed?
About one flight in five arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 21.3% of the 2,930 flights in this analysis, against 22.4% nationally. Delayed flights are late by an hour and a half on average.
Which airline is most reliable on IAH to PHX?
American Airlines leads at 81.6% on time across 622 flights. United Airlines is at the other end on 80.0%, a gap of 2 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 IAH to PHX?
The 5am–8am departure window is the strongest at 94.5% on time. The 8pm–5am window is the weakest at 67.3%, 27 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 IAH to PHX?
June is the weakest month at 67.9% on time, compared with 90.9% in February. Across the year that is 23 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 IAH — the return legseparate record
- George Bush Intercontinental (IAH) delay statistics
- Phoenix Sky Harbor International (PHX) delay statistics
- Envoy Air on-time record83.3%
- American Airlines on-time record81.6%
- United Airlines on-time record80.0%
- 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. IAH to PHX and PHX to IAH 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.