Route reliability record
IAH→PHX
Houston to Phoenix
- Flights
- 2,980
- Period
- September 2025 to August 2026
- Distance
- 1,009 mi
- Carriers
- 5
This route lands a B+, 3 points better than the national rate of 77.3%. About one flight in five arrives 15 minutes late or worse, and those flights are late by an hour and a half on average. That rests on 2,980 IAH to PHX flights, of which United Airlines flew 1,776 at 82.7% on time.
Best time to fly IAH to PHX: a 5am–8am departure, ideally on a Tuesday. Flights in that window arrived on time 94.5% of the time and Tuesday flights 84.3%, against 79.9% for the route overall.
The US average over the same twelve months is 77.3%, 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
79.9%
Arrivals under 15 minutes late, of 2,951 completed flights
Avg delay
87 min
Across delayed arrivals only, not all flights
Cancelled
0.74%
National rate is 1.89%
Best carrier
United
82.7% on time across 1,776 flights
These figures cover 2,980 flights between September 2025 and August 2026. The median arrival is 8 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 IAH to PHX
The two carriers here are closely matched: 3 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 | 81 | 87.7% | 244 min | 0.00% | A+ |
| United Airlines | 1,776 | 82.7% | 61 min | 0.23% | B+ |
| American Airlines | 632 | 80.0% | 151 min | 1.58% | B |
| SkyWest Airlinesthin sample | 185 | 68.3% | 73 min | 2.70% | C |
| Frontier Airlinesthin sample | 306 | 67.5% | 75 min | 0.98% | C+ |
No carrier stands out. United tops the table at 82.7%, 3 points clear of the bottom, which is inside the range this kind of sample moves year to year.
Flight by flight
Flights on IAH to PHX
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 Houston to Phoenix
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. IAH → PHXHouston to Phoenix | United Airlines | 82.5% | 82.7% | 0.23% | 5am–8am, Tue | UA 1895 09:40 |
| 2. IAH → PHXHouston to Phoenix | American Airlines | 78.7% | 80.0% | 1.58% | 8am–11am, Thu | — |
| 3. HOU → PHXHouston to Phoenix | Southwest Airlines | 76.4% | 76.8% | 0.53% | 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 24 points, against 3 points between the best and worst carrier.
- 5am–8am182 flights94.5%
- 8am–11am752 flights84.8%
- 11am–2pm283 flights77.6%
- 2pm–5pm888 flights81.1%
- 5pm–8pm380 flights74.7%
- 8pm–5am495 flights70.1%
Scale runs 60% to 100%.
Book the early departure. Flights leaving between 5am–8am arrive on time 94.5% of the time, against 70.1% for the overnight window. That is 24 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 888 flights scheduled in it.
Explore
Filter IAH to PHX 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 IAH to PHX, the best departure window is 5am–8am at 94.5% on time and the worst is 8pm–5am at 70.1%, a wide gap of 24.4 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am94.5%
- 8–11am84.8%
- 11am–2pm77.6%
- 2–5pm81.1%
- 5–8pm74.7%
- 8pm–5am70.1%
best all US flightsScale 60% to 100%.
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 84.3% on time and Sunday the weakest at 74.9%, a spread of 9 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 51,000 reported delay minutes.
- 42%Late-arriving aircraft
- 36%Carrier
- 15%National Airspace System
- 7%Extreme weather
42% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 51,000 reported delay minutes here, that single category outweighs weather by 6 to one. The split is drawn from 51,352 reported delay minutes.
The largest share of delay minutes, 36%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 18,000 of the 51,000 delay minutes reported here.
Cancellations are rare at 0.74%, 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
7.6% 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 an hour and a half, 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 81.8% on time across 2,977 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 2,980 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 PHX 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 90.9% 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. 2,951 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 arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 20.1% of the 2,980 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 IAH to PHX?
United Airlines leads at 82.7% on time across 1,776 flights. American Airlines is at the other end on 80.0%, a gap of 3 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 70.1%, 24 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
- United Airlines on IAH to PHX82.7%
- American Airlines on IAH to PHX80.0%
- SkyWest Airlines on IAH to PHX68.3%
- Frontier Airlines on IAH to PHX67.5%
- IAH to ORD, a related route75.1%
- DEN to PHX, a related route75.6%
- IAH to DFW, a related route76.4%
- Envoy Air on-time record87.7%
- United Airlines on-time record82.7%
- American Airlines on-time record80.0%
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.05 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.
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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.