Carrier route record

UAIAH→MEM

United Airlines · Houston to Memphis

Flights: 359
Period: July 2025 to June 2026
Share of route: 33%
Carriers: 2

Historical statistics for July 2025 to June 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, 6 points worse than the national rate of 77.6%. The late ones land about an hour behind schedule. That rests on 359 flights, with a median arrival 3 minutes early.

The national on-time rate over the same period is 77.6%, so United on IAH to MEM runs 6 points behind the country as a whole. Across a thousand flights that is about 61 extra late arrivals.

On time

71.5%

Arrivals under 15 minutes late, of 354 completed flights

Avg delay

57 min

Across delayed arrivals only, not all flights

Cancelled

1.39%

National rate is 1.81%

Whole route

79.5%

Every carrier on IAH to MEM, 1,084 flights

These figures cover 359 flights between July 2025 and June 2026. The median arrival is 3 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 IAH to MEM

United flew 359 of the 1,084 flights on IAH to MEM, about 33% of it. Its 71.5% on time is 8 points worse than the route as a whole, which runs 79.5%. Ranked by on-time rate it is last of two carriers on the route, where the range runs from SkyWest at 83.4% to United at 71.5%.

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.

On-time performance by carrier on IAH to MEM
Airline	Flights	On time	Avg delay	Cancelled	Grade
SkyWest Airlines	725	83.4%	67 min	0.83%	B+
United Airlines (this page)thin sample	359	71.5%	57 min	1.39%	C

Flight by flight

United flight numbers on IAH to MEM

UA 179420:0571.6% · 339 flights

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 359 flights.

The overnight block holds up unusually well at 71.6% on time across 354 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 354 flights scheduled in it.

Across the year

United on IAH to MEM through the year

Jul–Sep 202585 flights75.0%
Oct–Dec 202590 flights62.2%
Jan–Mar 202690 flights73.6%
Apr–Jun 202694 flights75.3%

Scale runs 55% to 80%. Rows with fewer than 30 flights show a dash.

Monthly volumes are too low here to break the year into twelve reliable readings. What the twelve-month total says is 71.5% on time across 359 flights.

United on IAH to MEM did not run the same all year. Its best quarter was Apr–Jun 2026 at 75.3% on time and its weakest Oct–Dec 2025 at 62.2%, a swing of 13 points on roughly 90 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 82.0% on time and Monday the weakest at 62.7%. 19 points is a smaller lever than departure hour, but it is free.

Delay causes

Why United runs late on this route

One category carries most of the weight here. Late-arriving aircraft accounts for 48% of the 5,802 delay minutes carriers reported, and the remaining four split what is left. The split is by minutes rather than by flights, so a few very long delays count for as much as many short ones.

Late-arriving aircraft
48%
Carrier
39%
National Airspace System
9%
Extreme weather
4%

48% 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 5,802 reported delay minutes here, that single category outweighs weather by 12 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 5,802 reported delay minutes.

The largest share of delay minutes, 39%, 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 2,245 of the 5,802 delay minutes reported here.

Cancellations sit at 1.39% against a national 1.81%, which is ordinary. Diversions add another 0.00%.

Connections and stage length

What a delay here costs

6.8% 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 last about an hour, 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 84.5% on time across 360 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. 359 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. 359 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 71.5% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 354 completed flights over 12 months sit behind that.

Where to go next

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.

Key figures