Route reliability record
SAT→IAH
San Antonio to Houston
- Flights
- 2,372
- Period
- September 2025 to August 2026
- Distance
- 191 mi
- Carriers
- 2
This route lands a B+, 6 points better than the national rate of 77.3%. About one flight in six arrives 15 minutes late or worse, and those flights are late by about an hour on average. That rests on 2,372 SAT to IAH flights, with a median arrival 7 minutes early.
Best time to fly SAT to IAH: a 11am–2pm departure, ideally on a Tuesday. Flights in that window arrived on time 89.3% of the time and Tuesday flights 86.7%, against 83.0% for the route overall.
Set against the rest of the country, this route's record is 6 points better than the US average of 77.3%. That gap is worth roughly 57 fewer late arrivals for every thousand flights.
Key figures
On time
83.0%
Arrivals under 15 minutes late, of 2,359 completed flights
Avg delay
59 min
Across delayed arrivals only, not all flights
Cancelled
0.46%
National rate is 1.89%
Best carrier
United
82.8% on time across 2,245 flights
These figures cover 2,372 flights between September 2025 and August 2026. The median arrival is 7 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.
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Carrier by carrier
Which airline is most reliable on SAT 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 | 127 | 87.3% | 69 min | 0.79% | A+ |
| United Airlines | 2,245 | 82.8% | 59 min | 0.45% | B+ |
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Best ways to make this trip
The most reliable ways to fly San Antonio to Houston
Every airline on this route and on the routes between nearby airports, ranked by how often a scheduled flight actually operated and arrived on time. 1 of the top 2 use a different airport at one end.
| Option | Airline | Success | On time | Cancelled | Best departure | Most punctual flight |
|---|---|---|---|---|---|---|
| 1. SAT → IAHSan Antonio to Houston | United Airlines | 82.4% | 82.8% | 0.45% | 11am–2pm, Tue | — |
| 2. SAT → HOUSan Antonio to Houston | Southwest Airlines | 74.6% | 74.8% | 0.31% | 5am–8am, Tue | — |
Success is the share of scheduled flights that operated and arrived less than 15 minutes late, so a cancelled flight counts against it. “(route)” means the best time comes from every carrier on the route rather than this airline alone.
Departure window
The best time of day to leave
Departure time is the single lever a traveller controls, and it moves the odds more than most people expect. Each bar below is the on-time rate for flights scheduled to leave inside that window, across 2,372 flights.
- 5am–8am608 flights85.7%
- 8am–11am350 flights83.6%
- 11am–2pm243 flights89.3%
- 2pm–5pm645 flights79.4%
- 5pm–8pm526 flights81.3%
- 8pm–5am—
Scale runs 70% to 95%. Rows with fewer than 30 flights show a dash.
The best window here is not the first bank but the 11am–2pm slot at 89.3% on time, ahead of 2pm–5pm at 79.4%. 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 2pm–5pm window is the busiest, with 645 flights scheduled in it.
Explore
Filter SAT to IAH by airline, time, month and day
Pick a breakdown and a carrier. The dashed mark on each row is the same slice for every US flight.
On SAT to IAH, the best departure window is 11am–2pm at 89.3% on time and the worst is 2pm–5pm at 79.4%, a real gap of 9.9 points. All US flights leaving 11am–2pm ran 78.3%.
- 5–8am85.7%
- 8–11am83.6%
- 11am–2pm89.3%
- 2–5pm79.4%
- 5–8pm81.3%
- 8pm–5am—
best all US flightsScale 60% to 95%. Cells under 30 flights show a dash.
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.
Delays peak in October, when the on-time rate falls to 72.2%. August is the strongest month at 92.6%. Moving a flexible trip across that boundary buys 20 points. March was the busiest month here, with 233 flights.
Across the week, Tuesday is the strongest day at 86.7% on time and Friday the weakest at 80.0%, a spread of 7 points.
Delay causes
Why this route gets delayed
National Airspace System accounts for 50% of the 24,000 delay minutes carriers reported here, and the remaining four split what is left.
- 50%National Airspace System
- 25%Late-arriving aircraft
- 23%Carrier
- 2%Extreme weather
50% 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 12,000 minutes out of 24,000, against a national NAS share of 21%. The split is drawn from 23,721 reported delay minutes.
Cancellations are rare at 0.46%, below the national 1.89% 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
Badly late arrivals are rare here: only 4.8% land an hour or more behind schedule, against 8.3% nationally. Connections built on this flight are about as safe as US domestic connections get, though a cancelled flight still ignores every layover you give it.
At 191 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 11am–2pm window matters as much as it does.
The return leg runs 83.1% on time across 2,373 flights, within half a point of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.
The sample behind these figures is 2,372 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.
Work out the risk of missing a connection in IAH after this flight
What to do with this
Booking this route
Put together: the calendar is the biggest lever here, not the carrier or the hour. August runs 92.6% on time and October 72.2%, a swing of 20 points. If the dates move at all, move them out of October before you think about anything else. 2,359 completed flights over 12 months sit behind that.
Common questions
SAT to IAH questions
How often is SAT 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 17.0% of the 2,372 flights in this analysis, against 22.7% nationally. Delayed flights are late by about an hour on average.
How reliable is SAT to IAH compared with the rest of the country?
83.0% of flights arrive on time here against a national 77.3%, 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 SAT to IAH?
The 11am–2pm departure window is the strongest at 89.3% on time. The 2pm–5pm window is the weakest at 79.4%, 10 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 SAT to IAH?
October is the weakest month at 72.2% on time, compared with 92.6% in August. 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 SAT — the return legseparate record
- San Antonio International (SAT) delay statistics
- George Bush Intercontinental (IAH) delay statistics
- SkyWest Airlines on SAT to IAH87.3%
- United Airlines on SAT to IAH82.8%
- SAT to DFW, a related route79.4%
- ORD to IAH, a related route76.0%
- SAT to DEN, a related route82.1%
- SkyWest Airlines on-time record87.3%
- United Airlines on-time record82.8%
- The best time of day to fly, according to 7.05 million flight records
- Worst months to fly in the US, ranked by the data
Direction matters. SAT to IAH and IAH to SAT 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, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.