Carrier route record

UAPDX→IAH

United Airlines · Portland to Houston

Flights: 880
Period: July 2025 to June 2026
Share of route: 71%
Carriers: 2

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

United on PDX 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 880 flights, with a median arrival 10 minutes early.

Set against the rest of the country, United's PDX to IAH record is 9 points better than the US average of 77.6%. That gap is worth roughly 88 fewer late arrivals for every thousand flights.

On time

86.4%

Arrivals under 15 minutes late, of 873 completed flights

Avg delay

75 min

Across delayed arrivals only, not all flights

Cancelled

0.57%

National rate is 1.81%

Whole route

85.4%

Every carrier on PDX to IAH, 1,233 flights

These figures cover 880 flights between July 2025 and June 2026. The median arrival is 10 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 PDX to IAH

United flew 880 of the 1,233 flights on PDX to IAH, most of the route. Its 86.4% on time is about level with the route as a whole at 85.4%. Ranked by on-time rate it is first of two carriers on the route, where the range runs from United at 86.4% to Alaska at 83.1%. One 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.

On-time performance by carrier on PDX to IAH
Airline	Flights	On time	Avg delay	Cancelled	Grade
United Airlines (this page)	880	86.4%	75 min	0.57%	A+
Alaska Airlinesthin sample	353	83.1%	44 min	0.85%	B+

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 15 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–8am365 flights93.3%
8am–11am—
11am–2pm268 flights78.7%
2pm–5pm96 flights81.2%
5pm–8pm—
8pm–5am151 flights86.6%

Scale runs 70% to 100%. Rows with fewer than 30 flights show a dash.

The weak window here is the middle of the day, not the evening: 11am–2pm runs 78.7% on time against 93.3% for 5am–8am. That shape usually means a departure bank rather than an accumulating delay, so the recovery later in the afternoon is real rather than noise. The 5am–8am window is the busiest, with 365 flights scheduled in it.

Across the year

United on PDX to IAH through the year

Darker means more delays. Figures are on-time percentages.January best, July worst

July is the worst month at 76.1% on time, 18 points below January, the best at 94.0%. 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. July was the busiest month here, with 92 flights.

Across the week, Sunday is the strongest day at 92.0% on time and Friday the weakest at 80.8%. 11 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 8,897 reported delay minutes.

Late-arriving aircraft
37%
Carrier
32%
National Airspace System
30%
Extreme weather
1%

37% 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 8,897 reported delay minutes here, that single category outweighs weather by 32 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 8,897 reported delay minutes.

The practical consequence: the 5am–8am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 93.3% on time here.

Cancellations are rare at 0.57%, 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 stage length

What a delay here costs

5.2% 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.

At 1,825 miles this is transcontinental flying, and long routes get a quiet structural advantage. Scheduled block time on a flight this length carries more padding in absolute minutes, so a twenty-minute late departure often still becomes an on-time arrival. Read the on-time rate here as slightly flattering next to a short-haul route with the same operational quality.

The return leg is a different operation and performs like one: it runs 82.0% on time across 880 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. 880 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 PDX to IAH

Put together: treat all of this as provisional. 880 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 86.4% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 873 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