Carrier performance at one airport

UA→IAH

United Airlines at George Bush Intercontinental

Departures: 74,201
Period: September 2025 to August 2026
Routes: 25
Rank here: #3 of 11

United Airlines at Houston lands a B+, 3 points better than the national rate of 77.3%. About one flight in five arrives 15 minutes late or worse, and those flights are late by about an hour on average. That rests on 74,201 flights, of which Delta Air Lines flew 8,429 at 81.0% on time.

Measured against the airport rather than the country, United Airlines runs about a point ahead of the 79.1% weighted average across all carriers at IAH. That is the comparison worth making: every operator here works the same runways, the same airspace and the same weather.

On time

80.6%

73,600 completed departures

Avg delay

63 min

Across delayed flights only

Cancelled

0.55%

At IAH, this carrier only

Rank here

Of 11 carriers clearing the floor at IAH

These figures cover 74,000 flights between September 2025 and August 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.

Against the competition

Every carrier at IAH, ranked

The choice of carrier is not cosmetic here. Delta Air Lines arrives on time 81.0% of the time; JetBlue Airways manages 50.5%. Sample sizes sit next to every figure, because a two-point gap across 835 flights means less than a ten-point one.

On-time performance of all carriers departing IAH
Airline	Flights	On time	Avg delay	Cancelled	Grade
Delta Air Lines	8,429	81.0%	83 min	1.90%	B
Alaska Airlines	1,195	80.6%	55 min	0.67%	B+
United Airlines (this page)	74,201	80.6%	63 min	0.55%	B+
Envoy Air	1,270	78.0%	91 min	1.81%	B
SkyWest Airlines	14,187	77.8%	94 min	1.02%	B
American Airlines	7,927	77.5%	122 min	2.35%	B
Republic Airways	873	74.8%	79 min	4.12%	C−
Spirit Airlines	4,114	74.5%	73 min	3.23%	C−
Frontier Airlines	5,339	70.9%	86 min	2.38%	C
PSA Airlines	566	68.1%	123 min	6.89%	C−
JetBlue Airways	835	50.5%	103 min	4.79%	F−

PSA Airlines cancels 6.9% of what it schedules here, the highest in the table. A cancelled flight never appears in an on-time rate, so read that column alongside the punctuality one rather than after it.

Route by route

Where United Airlines flies from IAH

United Airlines operates 25 routes out of IAH with enough volume to report. Route records inside one carrier at one airport still spread widely, because a short shuttle and a transcontinental have very different exposure to a late inbound.

United Airlines routes from IAH
Route	Flights	On time	Avg delay	Cancelled	Grade
IAH to ORD · Chicago	4,084	78.2%	69 min	0.59%	B+
IAH to DEN · Denver	3,894	83.6%	67 min	0.23%	B+
IAH to SFO · San Francisco	3,578	78.2%	62 min	0.42%	B+
IAH to EWR · Newark	3,510	75.2%	72 min	1.57%	B
IAH to LAX · Los Angeles	3,421	85.7%	57 min	0.20%	A+
IAH to MSY · New Orleans	2,739	83.9%	60 min	0.11%	B+
IAH to AUS · Austin	2,645	80.1%	62 min	0.72%	B+
IAH to LAS · Las Vegas	2,598	85.2%	60 min	0.27%	A+
IAH to DFW · Dallas-Fort Worth	2,459	76.8%	72 min	1.42%	B
IAH to MCO · Orlando	2,443	86.5%	71 min	0.53%	A+
IAH to DCA · Washington	2,385	76.7%	69 min	0.67%	B+
IAH to LGA · New York	2,376	71.3%	77 min	1.47%	C
IAH to SAT · San Antonio	2,247	83.0%	58 min	0.36%	B+
IAH to FLL · Fort Lauderdale	1,893	85.6%	59 min	0.58%	A+
IAH to IAD · Washington	1,860	82.4%	62 min	0.43%	B+
IAH to PHX · Phoenix	1,776	82.7%	61 min	0.23%	B+
IAH to SAN · San Diego	1,686	81.0%	55 min	0.18%	B+
IAH to BOS · Boston	1,549	76.1%	72 min	1.10%	B
IAH to MIA · Miami	1,438	82.0%	57 min	0.28%	B+
IAH to TPA · Tampa	1,336	83.5%	60 min	0.30%	B+
IAH to ATL · Atlanta	1,283	79.8%	64 min	0.47%	B+
IAH to SEA · Seattle	1,230	79.9%	52 min	0.08%	B+
IAH to SNA · Santa Ana	1,092	88.5%	45 min	0.00%	A+
IAH to BNA · Nashville	1,053	74.7%	57 min	0.47%	C+
IAH to PHL · Philadelphia	954	81.5%	69 min	0.94%	B+

Flight by flight

United Airlines flight numbers from IAH

91 United Airlines flight numbers leaving IAH flew their main route often enough to have a record of their own. Grouped by destination.

Departure window

Best time of day for this operation

Departure time matters more here than the choice of carrier. The gap between the best and worst window is 19 points, against 31 points between the best and worst carrier.

5am–8am10,175 flights92.2%
8am–11am11,299 flights84.7%
11am–2pm11,649 flights82.3%
2pm–5pm13,014 flights78.1%
5pm–8pm12,518 flights73.5%
8pm–5am15,546 flights76.8%

Scale runs 65% to 100%.

Book the early departure. Flights leaving between 5am–8am arrive on time 92.2% of the time, against 73.5% for the evening window. That is 19 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 8pm–5am window is the busiest, with 15,546 flights scheduled in it.

Across the year

Seasonal pattern

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

June is the worst month at 69.9% on time, 18 points below January, the best at 88.1%. 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. March was the busiest month here, with 6,498 flights.

Delay causes

What holds this operation up

Late-arriving aircraft
35%
National Airspace System
33%
Carrier
27%
Extreme weather
5%
Security
0%

35% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 891,000 reported delay minutes here, that single category outweighs weather by 7 to one. The split is drawn from 891,396 reported delay minutes.

Cancellations are rare at 0.55%, below the national 1.89% 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.

6.6% 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 an hour, which a normal layover absorbs.

74,201 flights sit behind these numbers, which is a large enough sample that the headline rate is not moving on noise. Where a sub-group falls below 30 flights the site shows a dash instead of a percentage.

Put together: the calendar is the biggest lever here, not the carrier or the hour. January runs 88.1% on time and June 69.9%, a swing of 18 points. If the dates move at all, move them out of June before you think about anything else. 73,600 completed flights over 12 months sit behind that.

Common questions

United Airlines at IAH

How often is United Airlines at IAH delayed?

About one flight in five arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 19.4% of the 74,201 flights in this analysis, against 22.7% nationally. Delayed flights are late by about an hour on average.

Which airline is most reliable on United Airlines at IAH?

Delta Air Lines leads at 81.0% on time across 8,429 flights. JetBlue Airways is at the other end on 50.5%, a gap of 31 points. Sample size matters as much as the percentage: a rate built from a few hundred flights moves around far more than one built from ten thousand.

What time of day has the fewest delays on United Airlines at IAH?

The 5am–8am departure window is the strongest at 92.2% on time. The 5pm–8pm window is the weakest at 73.5%, 19 points behind. Later departures inherit delays from earlier flights the same aircraft has already flown, which is why the curve slopes the way it does.

How bad are June delays on United Airlines at IAH?

June is the weakest month at 69.9% on time, compared with 88.1% in January. Across the year that is 18 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.

Where to go next

Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated 22 October 2026; recomputed monthly. How this data is collected.

Key figures