Route reliability record
EWR→IAH
Newark to Houston
- Flights
- 3,798
- Period
- July 2025 to June 2026
- Distance
- 1,400 mi
- Carriers
- 2
This route lands a B, 2 points better than the national rate of 77.6%. About one flight in five arrive 15 minutes late or worse, and those flights are late by a little over an hour on average. That is a workable record, not a spotless one. That rests on 3,798 flights, with a median arrival 11 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
79.6%
Arrivals under 15 minutes late, of 3,711 completed flights
Avg delay
75 min
Across delayed arrivals only, not all flights
Cancelled
2.08%
National rate is 1.81%
Best carrier
United
80.4% on time across 3,534 flights
These figures cover 3,798 flights between July 2025 and June 2026. Beyond the headline rate, 8.4% 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 EWR to IAH
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 |
|---|---|---|---|---|---|
| United Airlines | 3,534 | 80.4% | 74 min | 1.64% | B |
| Spirit Airlinesthin sample | 264 | 67.8% | 88 min | 7.95% | 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 21 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–8am702 flights92.0%
- 8am–11am613 flights82.8%
- 11am–2pm543 flights82.4%
- 2pm–5pm742 flights74.2%
- 5pm–8pm799 flights73.4%
- 8pm–5am399 flights71.1%
Scale runs 65% to 95%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 92.0% of the time, against 71.1% for the overnight window. That is 21 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 5pm–8pm window is the busiest, with 799 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 20 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 67.8% on time, 20 points below September, the best at 87.5%. 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 342 flights.
Across the week, Monday is the strongest day at 83.7% on time and Saturday the weakest at 77.0%. 7 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 57,000 reported delay minutes.
- 39%Late-arriving aircraft
- 29%National Airspace System
- 28%Carrier
- 4%Extreme weather
- 0%Security
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 57,000 reported delay minutes here, that single category outweighs weather by 10 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 56,996 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 92.0% on time here.
Cancellations sit at 2.08% against a national 1.81%, which is ordinary. Diversions add another 0.21%.
Connections and stage length
What a delay here actually costs
8.4% of arrivals land an hour or more late, close to the national 8.1%. That is the figure that decides a connection, and it says a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route are the a little over an hour kind, which a normal layover absorbs.
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 74.6% on time across 3,800 flights, 5 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 5 points of difference.
The sample behind these figures is 3,798 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 87.5% on time and July 67.8%, a swing of 20 points. If the dates move at all, move them out of July before you think about anything else. 3,711 completed flights over 12 months sit behind that.
Common questions
EWR to IAH questions
How often is EWR to IAH delayed?
About one flight in five arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 20.4% of the 3,798 flights in this analysis, against 22.4% nationally. Delayed flights are late by a little over an hour on average.
How reliable is EWR to IAH compared with the rest of the country?
79.6% of flights arrive on time here against a national 77.6%, a difference of 2 points in its favour. That is worth a B on this site's grading scale.
What time of day has the fewest delays on EWR to IAH?
The 5am–8am departure window is the strongest at 92.0% on time. The 8pm–5am window is the weakest at 71.1%, 21 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 EWR to IAH?
July is the weakest month at 67.8% on time, compared with 87.5% in September. Across the year that is 20 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 EWR — the return legseparate record
- Newark Liberty International (EWR) delay statistics
- George Bush Intercontinental (IAH) delay statistics
- United Airlines on-time record80.4%
- Spirit Airlines on-time record67.8%
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.04 million flight records
Direction matters. EWR to IAH and IAH to EWR 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.