Route reliability record
IAH→LGA
Houston to New York
- Flights
- 4,053
- Period
- July 2025 to June 2026
- Distance
- 1,416 mi
- Carriers
- 4
This route sits in the middle of the pack with a C. About seven flights in ten arrive on time by the DOT's definition, 5 points worse than the national rate of 77.6%. The late ones land a little over an hour behind schedule. That rests on 4,053 flights, of which Delta Air Lines flew 1,342 at 77.2% on time.
The national on-time rate over the same period is 77.6%, so this route runs 5 points behind the country as a whole. Across a thousand flights that is about 50 extra late arrivals.
Key figures
On time
72.6%
Arrivals under 15 minutes late, of 3,913 completed flights
Avg delay
81 min
Across delayed arrivals only, not all flights
Cancelled
2.74%
National rate is 1.81%
Best carrier
Delta
77.2% on time across 1,342 flights
These figures cover 4,053 flights between July 2025 and June 2026. Beyond the headline rate, 11.9% 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 IAH to LGA
The two carriers here are closely matched: 6 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 | 83.9% | 40 min | 3.12% | B− |
| Delta Air Lines | 1,342 | 77.2% | 95 min | 3.95% | B− |
| United Airlines | 2,382 | 71.4% | 75 min | 1.64% | C |
| Spirit Airlinesthin sample | 297 | 60.6% | 80 min | 6.06% | D− |
Delta Air Lines cancels 4.0% 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 22 points, against 6 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am660 flights86.0%
- 8am–11am875 flights83.0%
- 11am–2pm392 flights67.4%
- 2pm–5pm1,005 flights65.9%
- 5pm–8pm1,121 flights64.1%
- 8pm–5am—
Scale runs 55% to 90%. Rows with fewer than 30 flights show a dash.
The 5pm–8pm window is where this operation falls apart: 64.1% on time, against 86.0% 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 5pm–8pm window is the busiest, with 1,121 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 34 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.
Delays peak in March, when the on-time rate falls to 54.3%. January is the strongest month at 87.9%. Moving a flexible trip across that boundary buys 34 points. July was the busiest month here, with 380 flights.
Across the week, Saturday is the strongest day at 80.1% on time and Sunday the weakest at 65.3%. 15 points is a smaller lever than departure hour, but it is free.
Delay causes
Why this route gets delayed
One category carries most of the weight here. National Airspace System accounts for 48% of the 86,000 delay minutes carriers reported, and the remaining four split what is left. The split is by minutes rather than by flights, so a few very long delays count for as much as many short ones.
- 48%National Airspace System
- 26%Carrier
- 23%Late-arriving aircraft
- 3%Extreme weather
- 0%Security
48% of delay minutes are charged to the National Airspace System: air traffic volume, runway configuration, ground stops. No carrier can price its way out of that, which is why airport choice moves the number here more than carrier choice does. That is 41,000 minutes out of 86,000, against a national NAS share of 21%. The split is drawn from 86,261 reported delay minutes.
Cancellations run at 2.74%, against 1.81% nationally. That is roughly 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. 11.9% 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 76.5% on time across 4,060 flights, 4 points above 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 4,053 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. January runs 87.9% on time and March 54.3%, a swing of 34 points. If the dates move at all, move them out of March before you think about anything else. 3,913 completed flights over 12 months sit behind that.
Common questions
IAH to LGA questions
How often is IAH to LGA delayed?
Roughly 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 27.4% of the 4,053 flights in this analysis, against 22.4% nationally. Delayed flights are late by a little over an hour on average.
Which airline is most reliable on IAH to LGA?
Delta Air Lines leads at 77.2% on time across 1,342 flights. United Airlines is at the other end on 71.4%, a gap of 6 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 IAH to LGA?
The 5am–8am departure window is the strongest at 86.0% on time. The 5pm–8pm window is the weakest at 64.1%, 22 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 March delays on IAH to LGA?
March is the weakest month at 54.3% on time, compared with 87.9% in January. Across the year that is 34 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
- LGA to IAH — the return legseparate record
- George Bush Intercontinental (IAH) delay statistics
- LaGuardia (LGA) delay statistics
- SkyWest Airlines on-time record83.9%
- Delta Air Lines on-time record77.2%
- United Airlines on-time record71.4%
- What a cancellation rate actually tells you (and what it hides)
- The best time of day to fly, according to 7.04 million flight records
Direction matters. IAH to LGA and LGA to IAH 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.