Carrier route record
UAPHL→IAH
United Airlines · Philadelphia to Houston
- Flights
- 891
- Period
- July 2025 to June 2026
- Share of route
- 49%
- Carriers
- 6
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with United Airlines.
United on PHL to IAH earns an A. More than four flights in five arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 9 points better than the national rate of 77.6%. When something does go wrong the average delay runs a little over an hour. That rests on 891 flights, with a median arrival 15 minutes early.
Set against the rest of the country, United's PHL to IAH record is 9 points better than the US average of 77.6%. That gap is worth roughly 93 fewer late arrivals for every thousand flights.
Key figures
On time
86.9%
Arrivals under 15 minutes late, of 880 completed flights
Avg delay
81 min
Across delayed arrivals only, not all flights
Cancelled
1.01%
National rate is 1.81%
Whole route
80.1%
Every carrier on PHL to IAH, 1,829 flights
These figures cover 891 flights between July 2025 and June 2026. The median arrival is 15 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.
Carrier by carrier
United against every carrier on PHL to IAH
United flew 891 of the 1,829 flights on PHL to IAH, about 49% of it. Its 86.9% on time is 7 points better than the route as a whole, which runs 80.1%. Ranked by on-time rate it is first of six carriers on the route, where the range runs from United at 86.9% to Spirit at 60.0%. Four of those carriers flew fewer than 365 flights here, so treat their positions as rough.
Only one carrier clears this site's 365-flight floor here, so there is no comparison to draw. The table below is the full picture.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| United Airlines (this page) | 891 | 86.9% | 81 min | 1.01% | A |
| Republic Airwaysthin sample | 20 | 80.0% | 89 min | 0.00% | B+ |
| PSA Airlinesthin sample | 92 | 77.3% | 77 min | 2.17% | B |
| American Airlines | 714 | 74.1% | 87 min | 3.08% | C− |
| Frontier Airlinesthin sample | 70 | 68.1% | 60 min | 1.43% | C |
| Spirit Airlinesthin sample | 42 | 60.0% | 79 min | 4.76% | D− |
Departure window
When United runs best on this route
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 22 points, against half a point between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am113 flights93.8%
- 8am–11am231 flights89.9%
- 11am–2pm311 flights87.3%
- 2pm–5pm—
- 5pm–8pm170 flights83.4%
- 8pm–5am66 flights71.9%
Scale runs 65% to 100%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 93.8% of the time, against 71.9% for the overnight window. That is 22 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 11am–2pm window is the busiest, with 311 flights scheduled in it.
Across the year
United on PHL to IAH through the year
June is the worst month at 76.1% on time, 17 points below February, the best at 93.1%. 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. November was the busiest month here, with 89 flights.
Across the week, Tuesday is the strongest day at 90.1% on time and Saturday the weakest at 83.3%. 7 points is a smaller lever than departure hour, but it is free.
Delay causes
Why United runs late on this route
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 9,352 reported delay minutes.
- 42%National Airspace System
- 31%Carrier
- 28%Late-arriving aircraft
- 0%Extreme weather
42% of delay minutes are charged to the National Airspace System: air traffic volume, runway configuration, ground stops. No carrier can price its way out of that, which is why airport choice moves the number here more than carrier choice does. That is 3,897 minutes out of 9,352, against a national NAS share of 21%. The split is drawn from 9,352 reported delay minutes.
Cancellations sit at 1.01% against a national 1.81%, which is ordinary. Diversions add another 0.22%.
Connections and stage length
What a delay here costs
Badly late arrivals are rare here: only 4.7% land an hour or more behind schedule, against 8.1% nationally. Connections built on this flight are about as safe as US domestic connections get, though a cancelled flight still ignores every layover you give it.
The 1,325 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 83.0% on time across 891 flights, 4 points below 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.
One caution: this is a thin sample. 891 flights over twelve months is enough to clear this site's floor but not enough to pin the rate down tightly, and a single bad week moves it by more than a point. Treat the grade as a rough reading.
What to do with this
Booking United on PHL to IAH
Put together: treat all of this as provisional. 891 flights over twelve months is enough to clear this site's floor and not enough to be confident to better than a couple of points. The 86.9% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 880 completed flights over 12 months sit behind that.
Related
Where to go next
- PHL to IAH, every carrier
- United on IAH to PHL, the return leg
- American Airlines on PHL to IAH74.1%
- United Airlines network-wide record
- Philadelphia International (PHL) delay statistics
- George Bush Intercontinental (IAH) delay statistics
- The best time of day to fly, according to 7.04 million flight records
- Worst months to fly in the US, ranked by the data
Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.