Route reliability record
AUS→IAH
Austin to Houston
- Flights
- 2,674
- Period
- July 2025 to June 2026
- Distance
- 140 mi
- Carriers
- 2
This route sits in the middle of the pack with a B. Close to three flights in four arrive on time by the DOT's definition, 2 points worse than the national rate of 77.6%. The late ones land about an hour behind schedule. That rests on 2,674 flights, with a median arrival 2 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
75.6%
Arrivals under 15 minutes late, of 2,640 completed flights
Avg delay
62 min
Across delayed arrivals only, not all flights
Cancelled
1.23%
National rate is 1.81%
Best carrier
United
75.5% on time across 2,608 flights
These figures cover 2,674 flights between July 2025 and June 2026. The median arrival is 2 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 AUS 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 | 66 | 77.3% | 106 min | 0.00% | B+ |
| United Airlines | 2,608 | 75.5% | 61 min | 1.27% | 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 16 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–8am714 flights80.1%
- 8am–11am355 flights76.6%
- 11am–2pm300 flights72.4%
- 2pm–5pm652 flights73.4%
- 5pm–8pm619 flights74.3%
- 8pm–5am34 flights63.6%
Scale runs 55% to 85%. Rows with fewer than 30 flights show a dash.
The 8pm–5am window is where this operation falls apart: 63.6% on time, against 80.1% 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 714 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 31 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 October, when the on-time rate falls to 62.0%. February is the strongest month at 93.4%. Moving a flexible trip across that boundary buys 31 points. January was the busiest month here, with 239 flights.
Across the week, Saturday is the strongest day at 78.7% on time and Sunday the weakest at 70.4%. 8 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 42% of the 40,000 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.
- 42%National Airspace System
- 32%Late-arriving aircraft
- 20%Carrier
- 6%Extreme weather
42% 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 17,000 minutes out of 40,000, against a national NAS share of 21%. The split is drawn from 39,881 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 80.1% on time here.
Cancellations sit at 1.23% against a national 1.81%, which is ordinary. Diversions add another 0.04%.
Connections and stage length
What a delay here actually costs
6.6% 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 about an hour kind, which a normal layover absorbs.
At 140 miles this is a short hop, and stage length matters more than it looks. A flight this short spends under two hours in the air, which leaves almost nothing to claw back a late pushback with. Delay here is decided on the ground, in the turn, which is why the 5am–8am window matters as much as it does.
The return leg is a different operation and performs like one: it runs 79.4% on time across 2,675 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 2,674 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. February runs 93.4% on time and October 62.0%, a swing of 31 points. If the dates move at all, move them out of October before you think about anything else. 2,640 completed flights over 12 months sit behind that.
Common questions
AUS to IAH questions
How often is AUS 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 24.4% of the 2,674 flights in this analysis, against 22.4% nationally. Delayed flights are late by about an hour on average.
How reliable is AUS to IAH compared with the rest of the country?
75.6% of flights arrive on time here against a national 77.6%, a difference of 2 points against it. That is worth a B on this site's grading scale.
What time of day has the fewest delays on AUS to IAH?
The 5am–8am departure window is the strongest at 80.1% on time. The 8pm–5am window is the weakest at 63.6%, 16 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 October delays on AUS to IAH?
October is the weakest month at 62.0% on time, compared with 93.4% in February. Across the year that is 31 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 AUS — the return legseparate record
- Austin-Bergstrom International (AUS) delay statistics
- George Bush Intercontinental (IAH) delay statistics
- SkyWest Airlines on-time record77.3%
- United Airlines on-time record75.5%
- 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. AUS to IAH and IAH to AUS 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.