Route reliability record
PIT→IAH
Pittsburgh to Houston
- Flights
- 738
- Period
- July 2025 to June 2026
- Distance
- 1,117 mi
- Carriers
- 2
This route lands a B+, 6 points better than the national rate of 77.6%. About one flight in six arrives 15 minutes late or worse, and those flights are late by about an hour on average. That is a workable record, not a spotless one. That rests on 738 PIT to IAH flights, with a median arrival 11 minutes early.
Best time to fly PIT to IAH: a 11am–2pm departure, ideally on a Tuesday. Flights in that window arrived on time 93.1% of the time and Tuesday flights 86.7%, against 83.8% for the route overall.
Set against the rest of the country, this route's record is 6 points better than the US average of 77.6%. That gap is worth roughly 62 fewer late arrivals for every thousand flights.
Key figures
On time
83.8%
Arrivals under 15 minutes late, of 736 completed flights
Avg delay
66 min
Across delayed arrivals only, not all flights
Cancelled
0.14%
National rate is 1.81%
Best carrier
United
83.7% on time across 731 flights
These figures cover 738 flights between July 2025 and June 2026. The median arrival is 11 minutes early, which is the part an average hides: most flights here are fine, and the on-time rate is decided by a tail of badly late ones. On-time means under 15 minutes late, the DOT's own threshold.
Carrier by carrier
Which airline is most reliable on PIT 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 |
|---|---|---|---|---|---|
| SkyWest Airlinesthin sample | 7 | 100.0% | — | 0.00% | A+ |
| United Airlines | 731 | 83.7% | 66 min | 0.14% | B+ |
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 25 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–8am321 flights92.8%
- 8am–11am—
- 11am–2pm101 flights93.1%
- 2pm–5pm169 flights75.0%
- 5pm–8pm147 flights67.8%
- 8pm–5am—
Scale runs 60% to 100%. Rows with fewer than 30 flights show a dash.
The best window here is not the first bank but the 11am–2pm slot at 93.1% on time, ahead of 5pm–8pm at 67.8%. Where the curve peaks mid-day rather than at dawn, the constraint is usually congestion at one end rather than the aircraft's own rotation. The 5am–8am window is the busiest, with 321 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.
June is the worst month at 74.4% on time, 17 points below September, the best at 91.8%. 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. April was the busiest month here, with 88 flights.
Across the week, Tuesday is the strongest day at 86.7% on time and Sunday the weakest at 77.9%. 9 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 7,801 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
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 3,715 minutes out of 7,801, against a national NAS share of 21%. The split is drawn from 7,801 reported delay minutes.
Cancellations are rare at 0.14%, below the national 1.81% and low enough to earn the plus on the grade. Roughly one flight in 100 is called off; the risk here is arriving late, not not arriving.
Connections and stage length
What a delay here actually costs
5.8% 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 last about an hour, which a normal layover absorbs.
The 1,117 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 80.8% on time across 738 flights, 3 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 3 points of difference.
One caution: this is a thin sample. 738 flights over twelve months is enough to clear this site's floor but not enough to pin the rate down tightly, and a single bad week moves it by more than a point. Treat the grade as a rough reading.
Work out the risk of missing a connection in IAH after this flight
What to do with this
Booking this route
Put together: treat all of this as provisional. 738 flights over twelve months is enough to clear this site's floor and not enough to be confident to better than a couple of points. The 83.8% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 736 completed flights over 12 months sit behind that.
Common questions
PIT to IAH questions
How often is PIT to IAH delayed?
About one flight in six arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 16.2% of the 738 flights in this analysis, against 22.4% nationally. Delayed flights are late by about an hour on average.
How reliable is PIT to IAH compared with the rest of the country?
83.8% of flights arrive on time here against a national 77.6%, a difference of 6 points in its favour. That is worth a B+ on this site's grading scale.
What time of day has the fewest delays on PIT to IAH?
The 11am–2pm departure window is the strongest at 93.1% on time. The 5pm–8pm window is the weakest at 67.8%, 25 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 June delays on PIT to IAH?
June is the weakest month at 74.4% on time, compared with 91.8% 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 PIT — the return legseparate record
- Pittsburgh International (PIT) delay statistics
- George Bush Intercontinental (IAH) delay statistics
- PIT to ORD, a related route78.6%
- ORD to IAH, a related route75.0%
- PIT to LGA, a related route80.9%
- SkyWest Airlines on-time record100.0%
- United Airlines on-time record83.7%
- 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. PIT to IAH and IAH to PIT are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
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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.