Route reliability record
LGA→IAH
New York to Houston
- Flights
- 4,060
- Period
- July 2025 to June 2026
- Distance
- 1,416 mi
- Carriers
- 4
This route lands a B, about a point worse than the national rate of 77.6%. About one flight in four arrive 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 4,060 flights, of which United Airlines flew 2,382 at 77.1% on time.
The US average over the same twelve months is 77.6%, so there is little to separate this route from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
76.5%
Arrivals under 15 minutes late, of 3,941 completed flights
Avg delay
85 min
Across delayed arrivals only, not all flights
Cancelled
2.59%
National rate is 1.81%
Best carrier
United
77.1% on time across 2,382 flights
These figures cover 4,060 flights between July 2025 and June 2026. Beyond the headline rate, 9.8% 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
Which airline is most reliable on LGA to IAH
The two carriers here are closely matched: 3 points separate the best from the worst. At that spread, schedule and price are better tie-breakers than reliability. Sample sizes are shown so you can see which rows are worth weighing.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| SkyWest Airlinesthin sample | 32 | 80.6% | 38 min | 3.12% | B− |
| Spirit Airlinesthin sample | 304 | 79.8% | 65 min | 3.95% | B− |
| United Airlines | 2,382 | 77.1% | 87 min | 1.76% | B |
| Delta Air Lines | 1,342 | 74.5% | 85 min | 3.73% | C− |
Delta Air Lines cancels 3.7% 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.
Departure window
The best time of day to leave
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 30 points, against 3 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am925 flights90.9%
- 8am–11am842 flights82.5%
- 11am–2pm688 flights77.6%
- 2pm–5pm728 flights67.7%
- 5pm–8pm596 flights60.5%
- 8pm–5am281 flights64.6%
Scale runs 50% to 95%. Rows with fewer than 30 flights show a dash.
The 5pm–8pm window is where this operation falls apart: 60.5% on time, against 90.9% 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 925 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 17 points from best month to worst, which is wide. An annual average tells you very little about the week you are actually flying, so read the strip rather than the headline if your dates are fixed.
July is the worst month at 69.1% on time, 17 points below September, the best at 86.1%. 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. July was the busiest month here, with 380 flights.
Across the week, Tuesday is the strongest day at 79.9% on time and Sunday the weakest at 71.6%. 8 points is a smaller lever than departure hour, but it is free.
Delay causes
Why this route gets delayed
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 78,000 reported delay minutes.
- 36%Carrier
- 33%Late-arriving aircraft
- 25%National Airspace System
- 6%Extreme weather
- 0%Security
The largest share of delay minutes, 36%, 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 28,000 of the 78,000 delay minutes reported here. The split is drawn from 78,463 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 90.9% on time here.
Cancellations run at 2.59%, against 1.81% nationally. That is about one flight in 40 cancelled outright. A cancelled flight is invisible in every on-time figure on this page, so the punctuality numbers above describe only the flights that actually operated.
Connections and stage length
What a delay here actually costs
For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 9.8% 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 72.6% on time across 4,053 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.
The sample behind these figures is 4,060 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 this route
Put together: the calendar is the biggest lever here, not the carrier or the hour. September runs 86.1% on time and July 69.1%, a swing of 17 points. If the dates move at all, move them out of July before you think about anything else. 3,941 completed flights over 12 months sit behind that.
Common questions
LGA to IAH questions
How often is LGA to IAH delayed?
About one flight in four arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 23.5% of the 4,060 flights in this analysis, against 22.4% nationally. Delayed flights are late by an hour and a half on average.
Which airline is most reliable on LGA to IAH?
United Airlines leads at 77.1% on time across 2,382 flights. Delta Air Lines is at the other end on 74.5%, a gap of 3 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 LGA to IAH?
The 5am–8am departure window is the strongest at 90.9% on time. The 5pm–8pm window is the weakest at 60.5%, 30 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 July delays on LGA to IAH?
July is the weakest month at 69.1% on time, compared with 86.1% in September. Across the year that is 17 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.
Related
Where to go next
- IAH to LGA — the return legseparate record
- LaGuardia (LGA) delay statistics
- George Bush Intercontinental (IAH) delay statistics
- SkyWest Airlines on-time record80.6%
- Spirit Airlines on-time record79.8%
- United Airlines on-time record77.1%
- Why the first flight of the morning is statistically safest
- What a cancellation rate actually tells you (and what it hides)
Direction matters. LGA to IAH and IAH to LGA are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Updated monthly. How this data is collected.