Houston (IAH) to San Antonio (SAT): On-Time Performance
Data through May 2026
The calendar drives reliability on IAH–SAT. February 2026 flights landed on schedule 91% of the time, but July 2024 dropped to 55% — a gap of 36 points. Across the full period the route averages 80% on-time against a national 78%. Morning departures also hold up better than evening ones (88% vs 74%), which matters most in the rough months.
- On-time
- 80%
- arrived <15 min late
- Avg delay
- 14 min
- completed flights
- Cancelled
- 1.2%
- Flights/day
- 6.7
- last 12 months
- Duration
- 1h 8m
- scheduled
- Distance
- 191 mi
Best airline from IAH to SAT
2 airlines flew this route regularly between 2024-06 and 2026-05.
| Airline | On-time | Avg delay | Cancelled | Flights |
|---|---|---|---|---|
| United Airlinesmost reliable | 80% | 14 min | 1.3% | 4,546 |
| SkyWest Airlines | 76% | 17 min | 0.8% | 266 |
Monthly on-time trend
Best time to fly from IAH to SAT
Aim for departures around 7 a.m. (93% on-time); avoid 5 p.m. departures (46%).
By day of week
| Day | On-time | Avg delay |
|---|---|---|
| Monday | 77% | 17 min |
| Tuesdaybest | 84% | 10 min |
| Wednesday | 81% | 14 min |
| Thursday | 79% | 14 min |
| Friday | 77% | 15 min |
| Saturday | 83% | 13 min |
| Sunday | 80% | 14 min |
What causes delays on this route
Share of total delay minutes by cause, as reported by carriers to the US DOT.
- Late-arriving aircraft44%
- Airline operations37%
- National airspace system13%
- Weather7%
Frequently asked questions
- How often are flights from IAH to SAT delayed?
- 20% of IAH–SAT flights arrived 15 or more minutes late (the US DOT definition of a delay) between 2024-06 and 2026-05. The average arrival delay across completed flights was 14 minutes.
- Which airline is most reliable from IAH to SAT?
- United Airlines has the best on-time record on this route at 80%, based on 4,546 flights. 2 airlines flew IAH–SAT frequently enough to compare in this period.
- What is the best time of day to fly from IAH to SAT?
- Departures around 7 a.m. have the best record (93% on-time), while departures around 5 p.m. have the worst (46%). As on most US routes, delays accumulate through the day, so earlier flights are generally safer.
- How long is the flight from IAH to SAT?
- The scheduled IAH–SAT flight time averages 1h 8m over 191 miles. Actual arrival times vary — flights on this route land 15+ minutes late 20% of the time.
- How often are IAH to SAT flights cancelled?
- 1.2% of scheduled flights on this route were cancelled between 2024-06 and 2026-05, at or below the national rate of 1.6%.
- What is the worst month to fly from IAH to SAT?
- July 2024 was the roughest month in this dataset, with only 55% of arrivals on time. The best was February 2026 at 91%. If your dates are flexible, that 36-point gap is worth planning around.
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Based on 4,812 flights, 2024-06–2026-05. Source: US DOT Bureau of Transportation Statistics. Updated 2026-07-01.