Flight number record

UA 678

United Airlines · McAllen to Houston

Route: MFE → IAH
Departs: 07:00
Flights: 363
Period: July 2025 to June 2026

Historical statistics for July 2025 to June 2026, not live status. For today’s UA 678, check with United Airlines.

UA 678 earns a B+. More than four flights in five arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 7 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 363 flights, with a median arrival 7 minutes early.

Set against the rest of the country, UA 678's record is 7 points better than the US average of 77.6%. That gap is worth roughly 72 fewer late arrivals for every thousand flights.

On time

84.8%

Arrivals under 15 minutes late, of 361 completed flights

Avg delay

80 min

Across delayed arrivals only, not all flights

Cancelled

0.55%

National rate is 1.81%

1 hour+ late

5.3%

National rate is 8.1%

These figures cover 363 flights between July 2025 and June 2026. The median arrival is 7 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.

Schedule

When UA 678 flies

UA 678 is scheduled to leave McAllen (MFE) at 07:00 local time and reach Houston (IAH) at 08:19. That slot held for 339 of the 363 scheduled departures in the data, so the figures below describe one steady operation rather than a number that moved around the clock.

Departs 07:00339 flights93.4%

Scale runs 0% to 100%. Rows with fewer than 30 flights show a dash.

Share of scheduled departures at each local time. Times used on fewer than one flight in ten are not listed.

A 07:00 departure sits in the 5am–8am window. Across every US flight scheduled in that window the on-time rate is 89.3%, and UA 678 runs 5 points worse at 84.8%. Early departures usually start with an aircraft that has not flown yet that day, which is most of why the window does well.

Against the route

UA 678 next to MFE to IAH

Every carrier on MFE to IAH combined arrived on time 81.6% of the time across 662 flights, so UA 678 is 3 points ahead of it. Across its whole network United Airlines managed 79.0%, which this flight beats by 6 points.

UA 678 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
UA 678thin sample	363	84.8%	80 min	0.55%	B+
All United Airlines on MFE–IAH	409	85.5%	76 min	0.49%	A+
All carriers on MFE–IAH	662	81.6%	97 min	0.76%	B+
United Airlines, whole network	821,041	79.0%	72 min	1.01%	B

Across the year

UA 678 quarter by quarter

UA 678 did not run the same all year. Its best quarter was Jan–Mar 2026 at 89.7% on time and its weakest Apr–Jun 2026 at 75.8%, a swing of 14 points on roughly 91 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.

Jul–Sep 202592 flights88.0%
Oct–Dec 202591 flights85.7%
Jan–Mar 202689 flights89.7%
Apr–Jun 202691 flights75.8%

Scale runs 65% to 95%. Rows with fewer than 30 flights show a dash.

By weekday, UA 678 did best on Friday at 94.1% on time and worst on Wednesday at 76.5%. Each day rests on about 52 flights, so a gap of 18 points is worth noticing but could still narrow in another year.

Delay causes

Why UA 678 runs late

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 4,397 reported delay minutes.

Carrier
41%
Late-arriving aircraft
30%
National Airspace System
30%

The largest share of delay minutes, 41%, 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 1,784 of the 4,397 delay minutes reported here. The split is drawn from 4,397 delay minutes reported on UA 678.

Cancellations are rare at 0.55%, below the national 1.81% 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 routes

What a delay on this flight costs

5.3% 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 a little over an hour, which a normal layover absorbs.

The same number turns up on three other city pairs in the data, including IAH to LGA (222), SBA to DEN (1) and BTV to DEN (1), but none flew often enough under UA 678 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to MFE to IAH only.

One caution: this is a thin sample. 363 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 UA 678

For a booking, read UA 678 as 84.8% on time with 0.55% cancelled over 363 flights. Those are rates from the past twelve months, not a forecast for any particular day.

Where to go next

A flight number here means United Airlines’s own number as it reports to the DOT. How the figures are computed is on the methodology page.

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