Route reliability record
IAH→EWR
Houston to Newark
- Flights
- 3,800
- Period
- July 2025 to June 2026
- Distance
- 1,400 mi
- Carriers
- 2
This route sits in the middle of the pack with a C. Close to three flights in four arrive on time by the DOT's definition, 3 points worse than the national rate of 77.6%. The late ones land a little over an hour behind schedule. That rests on 3,800 flights, with a median arrival 5 minutes early.
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
74.6%
Arrivals under 15 minutes late, of 3,716 completed flights
Avg delay
71 min
Across delayed arrivals only, not all flights
Cancelled
1.89%
National rate is 1.81%
Best carrier
United
74.5% on time across 3,534 flights
These figures cover 3,800 flights between July 2025 and June 2026. Beyond the headline rate, 9.9% 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 EWR
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.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Spirit Airlinesthin sample | 266 | 75.5% | 65 min | 6.39% | B− |
| United Airlines | 3,534 | 74.5% | 72 min | 1.56% | C |
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 28 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–8am768 flights89.3%
- 8am–11am645 flights80.4%
- 11am–2pm897 flights72.1%
- 2pm–5pm733 flights61.5%
- 5pm–8pm396 flights65.5%
- 8pm–5am361 flights75.4%
Scale runs 55% to 95%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 89.3% of the time, against 61.5% for the afternoon window. That is 28 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 11am–2pm window is the busiest, with 897 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 22 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 63.2% on time, 22 points below January, the best at 85.1%. 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 341 flights.
Across the week, Tuesday is the strongest day at 82.0% on time and Sunday the weakest at 70.1%. 12 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 47% of the 67,000 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.
- 47%National Airspace System
- 24%Carrier
- 23%Late-arriving aircraft
- 7%Extreme weather
- 0%Security
47% 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 31,000 minutes out of 67,000, against a national NAS share of 21%. The split is drawn from 67,307 reported delay minutes.
Cancellations sit at 1.89% against a national 1.81%, which is ordinary. Diversions add another 0.32%.
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. 9.9% 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 1,400 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 79.6% on time across 3,798 flights, 5 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 5 points of difference.
The sample behind these figures is 3,800 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 85.1% on time and July 63.2%, a swing of 22 points. If the dates move at all, move them out of July before you think about anything else. 3,716 completed flights over 12 months sit behind that.
Common questions
IAH to EWR questions
How often is IAH to EWR 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 25.4% of the 3,800 flights in this analysis, against 22.4% nationally. Delayed flights are late by a little over an hour on average.
How reliable is IAH to EWR compared with the rest of the country?
74.6% of flights arrive on time here against a national 77.6%, a difference of 3 points against it. That is worth a C on this site's grading scale.
What time of day has the fewest delays on IAH to EWR?
The 5am–8am departure window is the strongest at 89.3% on time. The 2pm–5pm window is the weakest at 61.5%, 28 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 IAH to EWR?
July is the weakest month at 63.2% on time, compared with 85.1% in January. Across the year that is 22 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
- EWR to IAH — the return legseparate record
- George Bush Intercontinental (IAH) delay statistics
- Newark Liberty International (EWR) delay statistics
- Spirit Airlines on-time record75.5%
- United Airlines on-time record74.5%
- The best time of day to fly, according to 7.04 million flight records
- Worst months to fly in the US, ranked by the data
Direction matters. IAH to EWR and EWR 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.