Carrier route record
UAIAH→MEM
United Airlines · Houston to Memphis
- Flights
- 356
- Period
- September 2025 to August 2026
- Share of route
- 33%
- Carriers
- 2
Historical statistics for September 2025 to August 2026, not live status. For today’s flights, check with United Airlines.
United on IAH to MEM 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 77.3%. The late ones land about 50 minutes behind schedule. That rests on 356 flights, with a median arrival 4 minutes early.
The national on-time rate over the same period is 77.3%, so United on IAH to MEM runs 5 points behind the country as a whole. Across a thousand flights that is about 49 extra late arrivals.
Key figures
On time
72.4%
Arrivals under 15 minutes late, of 352 completed flights
Avg delay
49 min
Across delayed arrivals only, not all flights
Cancelled
1.12%
National rate is 1.89%
Whole route
80.6%
Every carrier on IAH to MEM, 1,075 flights
These figures cover 356 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
United against every carrier on IAH to MEM
United flew 356 of the 1,075 flights on IAH to MEM, about 33% of it. Its 72.4% on time is 8 points worse than the route as a whole, which runs 80.6%. Ranked by on-time rate it is last of two carriers on the route, where the range runs from SkyWest at 84.7% to United at 72.4%.
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 |
|---|---|---|---|---|---|
| SkyWest Airlines | 719 | 84.7% | 68 min | 0.97% | B+ |
| United Airlines (this page)thin sample | 356 | 72.4% | 49 min | 1.12% | C |
Flight by flight
United flight numbers on IAH to MEM
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Departure window
When United runs best on this route
Departure time is the single lever a traveller controls, and it moves the odds more than most people expect. Each bar below is the on-time rate for flights scheduled to leave inside that window, across 356 flights.
The overnight block holds up unusually well at 72.8% on time across 346 flights. Red-eyes fly into empty airspace and empty gates, and they are the first rotation of the aircraft's day rather than the last. The 8pm–5am window is the busiest, with 346 flights scheduled in it.
Across the year
United on IAH to MEM through the year
- Jul–Sep 202530 flights90.0%
- Oct–Dec 202590 flights62.2%
- Jan–Mar 202690 flights73.6%
- Apr–Jun 202694 flights75.3%
- Jul–Sep 202652 flights73.1%
Scale runs 55% to 95%.
Monthly volumes are too low here to break the year into twelve reliable readings. What the twelve-month total says is 72.4% on time across 356 flights.
United on IAH to MEM did not run the same all year. Its best quarter was Jul–Sep 2025 at 90.0% on time and its weakest Oct–Dec 2025 at 62.2%, a swing of 28 points on roughly 71 flights a quarter. The twelve-month rate averages over that, so if you are flying in a weak quarter the quarter's own figure is the better guide.
Across the week, Wednesday is the strongest day at 86.3% on time and Monday the weakest at 67.3%, a spread of 19 points.
Arrival by arrival
How late United on IAH to MEM runs when it is late
The 97 late arrivals split 41 under half an hour, 36 between 30 and 60 minutes, and 20 an hour or more.
- 15+ min early73 flights20.7%
- Within 15 min182 flights51.7%
- 15–29 min late41 flights11.6%
- 30–59 min late36 flights10.2%
- 1–2 hours late11 flights3.1%
- 2+ hours late9 flights2.6%
Scale runs 0% to 100%.
Share of 352 completed flights by arrival against schedule.
13 of 92 late departures made up the time and arrived on time, 14% of them. In the other direction, 18 flights left on time yet arrived 15 minutes late or more, so that delay built up after pushback: in the air, in a holding pattern or on the ground at MEM.
The worst days
Worst days for United on IAH to MEM
The latest arrival of the period was on 7 March 2026, 3 hours 46 minutes behind schedule; most of its delay minutes were filed as a late-arriving aircraft. The same cause led on three of the five worst days.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 7 March 2026 | 3 hours 46 minutes | Late-arriving aircraft |
| 18 May 2026 | 3 hours 29 minutes | Late-arriving aircraft |
| 24 November 2025 | 3 hours 23 minutes | Carrier |
| 19 June 2026 | 2 hours 49 minutes | Carrier |
| 15 March 2026 | 2 hours 15 minutes | Late-arriving aircraft |
Delay causes
Why United runs late on this route
Carrier accounts for 44% of the 4,749 delay minutes carriers reported here, and the remaining four split what is left.
- 44%Carrier
- 39%Late-arriving aircraft
- 13%National Airspace System
- 4%Extreme weather
39% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 4,749 reported delay minutes here, that single category outweighs weather by 10 to one. The split is drawn from 4,749 reported delay minutes.
The largest share of delay minutes, 44%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 2,083 of the 4,749 delay minutes reported here.
Cancellations sit at 1.12% against a national 1.89%, which is ordinary. Diversions add another 0.00%.
Connections and stage length
What a delay here costs
5.7% 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 about 50 minutes, which a normal layover absorbs.
At 468 miles this is a short hop, and stage length matters more than it looks. A flight this short spends under two hours in the air, which leaves almost nothing to claw back a late pushback with. Delay here is decided on the ground, in the turn, which is why the 8pm–5am window matters as much as it does.
The return leg is a different operation and performs like one: it runs 85.6% on time across 352 flights, 13 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 13 points of difference.
One caution: this is a thin sample. 356 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 IAH to MEM
Put together: treat all of this as provisional. 356 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 72.4% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 352 completed flights over 12 months sit behind that.
Related
Where to go next
- IAH to MEM, every carrier
- United on MEM to IAH, the return leg
- SkyWest Airlines on IAH to MEM84.7%
- United Airlines network-wide record
- George Bush Intercontinental (IAH) delay statistics
- Memphis International (MEM) delay statistics
- Why the first flight of the morning is statistically safest
- The best day of the week to fly, and why it is the second lever
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.