Route reliability record
PHX→IAH
Phoenix to Houston
- Flights
- 2,977
- Period
- September 2025 to August 2026
- Distance
- 1,009 mi
- Carriers
- 5
This route lands a B+, 5 points better than the national rate of 77.3%. Roughly one flight in five arrives 15 minutes late or worse, and those flights are late by a little over an hour on average. That rests on 2,977 PHX to IAH flights, of which United Airlines flew 1,772 at 85.6% on time.
Best time to fly PHX to IAH: a 5am–8am departure, ideally on a Wednesday. Flights in that window arrived on time 91.6% of the time and Wednesday flights 85.8%, against 81.8% for the route overall.
Set against the rest of the country, this route's record is 5 points better than the US average of 77.3%. That gap is worth roughly 45 fewer late arrivals for every thousand flights.
Key figures
On time
81.8%
Arrivals under 15 minutes late, of 2,940 completed flights
Avg delay
74 min
Across delayed arrivals only, not all flights
Cancelled
0.77%
National rate is 1.89%
Best carrier
United
85.6% on time across 1,772 flights
These figures cover 2,977 flights between September 2025 and August 2026. The median arrival is 4 minutes early, which is the part an average hides: most flights here are fine, and the on-time rate is decided by a tail of badly late ones. On-time means under 15 minutes late, the DOT's own threshold.
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Carrier by carrier
Which airline is most reliable on PHX to IAH
The choice of carrier is not cosmetic here. United Airlines arrives on time 85.6% of the time; American Airlines manages 74.4%. Sample sizes sit next to every figure, because a two-point gap across 631 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| United Airlines | 1,772 | 85.6% | 82 min | 0.40% | A+ |
| Envoy Airthin sample | 83 | 81.7% | 56 min | 0.00% | B+ |
| Frontier Airlinesthin sample | 306 | 80.5% | 59 min | 0.65% | B+ |
| American Airlines | 631 | 74.4% | 65 min | 1.43% | C |
| SkyWest Airlinesthin sample | 185 | 72.2% | 79 min | 2.70% | C |
United leads American by 11 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.
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Best ways to make this trip
The most reliable ways to fly Phoenix to Houston
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. PHX → IAHPhoenix to Houston | United Airlines | 85.3% | 85.6% | 0.40% | 5am–8am, Wed | — |
| 2. PHX → IAHPhoenix to Houston | American Airlines | 73.3% | 74.4% | 1.43% | 8pm–5am, Sat | — |
| 3. PHX → HOUPhoenix to Houston | Southwest Airlines | 71.1% | 71.4% | 0.47% | 5am–8am, Tue | — |
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 21 points, against 11 points between the best and worst carrier.
- 5am–8am422 flights91.6%
- 8am–11am970 flights82.7%
- 11am–2pm666 flights83.3%
- 2pm–5pm418 flights77.5%
- 5pm–8pm405 flights71.0%
- 8pm–5am96 flights81.7%
Scale runs 65% to 95%.
Book the early departure. Flights leaving between 5am–8am arrive on time 91.6% of the time, against 71.0% for the evening window. That is 21 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 8am–11am window is the busiest, with 970 flights scheduled in it.
Explore
Filter PHX to IAH 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 PHX to IAH, the best departure window is 5am–8am at 91.6% on time and the worst is 5pm–8pm at 71.0%, a wide gap of 20.6 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am91.6%
- 8–11am82.7%
- 11am–2pm83.3%
- 2–5pm77.5%
- 5–8pm71.0%
- 8pm–5am81.7%
best all US flightsScale 60% to 95%.
Across the year
When delays peak on this route
This route's year swings by 16 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 74.0% on time, 16 points below February, the best at 90.1%. 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 301 flights.
Across the week, Wednesday is the strongest day at 85.8% on time and Friday the weakest at 78.1%, a spread of 8 points.
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 39,000 reported delay minutes.
- 40%Late-arriving aircraft
- 34%Carrier
- 24%National Airspace System
- 2%Extreme weather
40% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 39,000 reported delay minutes here, that single category outweighs weather by 20 to one. The split is drawn from 39,441 reported delay minutes.
The largest share of delay minutes, 34%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 13,000 of the 39,000 delay minutes reported here.
Cancellations are rare at 0.77%, below the national 1.89% 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
6.3% of arrivals land an hour or more late, close to the national 8.3%, so 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 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.
The return leg runs 79.9% on time across 2,980 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 2,977 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 IAH 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 90.1% on time and July 74.0%, a swing of 16 points. If the dates move at all, move them out of July before you think about anything else. 2,940 completed flights over 12 months sit behind that.
Common questions
PHX to IAH questions
How often is PHX to IAH delayed?
Roughly one flight in five arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 18.2% of the 2,977 flights in this analysis, against 22.7% nationally. Delayed flights are late by a little over an hour on average.
Which airline is most reliable on PHX to IAH?
United Airlines leads at 85.6% on time across 1,772 flights. American Airlines is at the other end on 74.4%, a gap of 11 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 PHX to IAH?
The 5am–8am departure window is the strongest at 91.6% on time. The 5pm–8pm window is the weakest at 71.0%, 21 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 PHX to IAH?
July is the weakest month at 74.0% on time, compared with 90.1% in February. Across the year that is 16 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
- IAH to PHX — the return legseparate record
- Phoenix Sky Harbor International (PHX) delay statistics
- George Bush Intercontinental (IAH) delay statistics
- United Airlines on PHX to IAH85.6%
- Frontier Airlines on PHX to IAH80.5%
- American Airlines on PHX to IAH74.4%
- SkyWest Airlines on PHX to IAH72.2%
- PHX to DEN, a related route76.7%
- ORD to IAH, a related route76.0%
- PHX to LAX, a related route82.1%
- United Airlines on-time record85.6%
- Envoy Air on-time record81.7%
- Frontier Airlines on-time record80.5%
- Same route, different airline: where the carrier you pick matters most
- Why the first flight of the morning is statistically safest
Direction matters. PHX to IAH and IAH to PHX 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.