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DelayAtlas

Carrier route record

UALGAIAH

United Airlines · New York to Houston

Flights
2,382
Period
July 2025 to June 2026
Share of route
59%
Carriers
4
BGRADE

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

United on LGA to IAH lands a B, level with the national rate of 77.6%. Roughly one flight in four arrives 15 minutes late or worse, and those flights are late by an hour and a half on average. That is a workable record, not a spotless one. That rests on 2,382 flights, with a median arrival 9 minutes early.

The US average over the same twelve months is 77.6%, so there is little to separate United on LGA to IAH from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.

Key figures

On time

77.1%

Arrivals under 15 minutes late, of 2,334 completed flights

Avg delay

87 min

Across delayed arrivals only, not all flights

Cancelled

1.76%

National rate is 1.81%

Whole route

76.5%

Every carrier on LGA to IAH, 4,060 flights

These figures cover 2,382 flights between July 2025 and June 2026. Beyond the headline rate, 9.1% of arrivals land a full hour or more behind schedule. That is the number that wrecks a connection, and it is not visible in an on-time percentage alone.

Carrier by carrier

United against every carrier on LGA to IAH

United flew 2,382 of the 4,060 flights on LGA to IAH, most of the route. Its 77.1% on time is about level with the route as a whole at 76.5%. Ranked by on-time rate it is number three of four carriers on the route, where the range runs from SkyWest at 80.6% to Delta at 74.5%. Two 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 LGA to IAH
AirlineFlightsOn timeAvg delayCancelledGrade
SkyWest Airlinesthin sample3280.6%38 min3.12%B−
Spirit Airlinesthin sample30479.8%65 min3.95%B−
United Airlines (this page)2,38277.1%87 min1.76%B
Delta Air Lines1,34274.5%85 min3.73%C−

Flight by flight

United flight numbers on LGA to IAH

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 32 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–8am573 flights91.7%
  • 8am–11am394 flights86.5%
  • 11am–2pm316 flights87.1%
  • 2pm–5pm572 flights64.9%
  • 5pm–8pm281 flights60.0%
  • 8pm–5am246 flights62.4%

Scale runs 50% to 95%. Rows with fewer than 30 flights show a dash.

The 5pm–8pm window is where this operation falls apart: 60.0% on time, against 91.7% for the 5am–8am slot. By evening the aircraft flying these rotations have absorbed a full day of small delays and there is no slack left to recover in. The 5am–8am window is the busiest, with 573 flights scheduled in it.

Across the year

United on LGA to IAH through the year

On-time rate by calendar month93J85F81M83A70M71J66J76A89S72O77N76D
Darker means more delays. Figures are on-time percentages.January best, July worst

July is the worst month at 66.4% on time, 26 points below January, the best at 92.6%. 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 233 flights.

Across the week, Saturday is the strongest day at 81.2% on time and Sunday the weakest at 73.2%. 8 points is a smaller lever than departure hour, but it is free.

On-time rate by day of the week75.9Mon79.8Tue76.3Wed74.6Thu79.7Fri81.2Sat73.2Sun
Monday: 75.9 percent on time. Tuesday: 79.8 percent on time. Wednesday: 76.3 percent on time. Thursday: 74.6 percent on time. Friday: 79.7 percent on time. Saturday: 81.2 percent on time. Sunday: 73.2 percent on time

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 47,000 reported delay minutes.

  • Late-arriving aircraft
    39%
  • Carrier
    27%
  • National Airspace System
    25%
  • Extreme weather
    8%

39% 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 47,000 reported delay minutes here, that single category outweighs weather by 5 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 46,550 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 91.7% on time here.

Cancellations sit at 1.76% against a national 1.81%, which is ordinary. Diversions add another 0.25%.

Connections and stage length

What a delay here costs

For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 9.1% of arrivals land a full hour or more behind schedule, against 8.1% nationally. A 45-minute layover does not survive that, and no amount of walking quickly changes it. Ninety minutes is the honest minimum here, and two hours if the onward flight is on a separate ticket.

The 1,416 miles between these two airports put this in the middle of the US network, around two and a half to three hours of block time. That is enough cruise to absorb a ten-minute late pushback and not enough to absorb thirty. It is also long enough that the aircraft usually flies three or four legs a day rather than six, which slows how fast delay compounds.

The return leg is a different operation and performs like one: it runs 71.4% on time across 2,382 flights, 6 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 6 points of difference.

The sample behind these figures is 2,382 flights, enough that the headline rate is stable to within roughly a point. The hour-block and month splits divide that further, so read the thinner bars with more caution than the headline.

What to do with this

Booking United on LGA to IAH

Put together: the calendar is the biggest lever here, not the carrier or the hour. January runs 92.6% on time and July 66.4%, a swing of 26 points. If the dates move at all, move them out of July before you think about anything else. 2,334 completed flights over 12 months sit behind that.

Related

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.