Houston (IAH) to St. Louis (STL): On-Time Performance
Data through May 2026
Houston (IAH) to St. Louis (STL) effectively runs on two schedules. In January 2026, 88% of arrivals were on time; in June 2025 that fell to 40% — a 48-point seasonal swing. Across the full period the route averages 71% on-time against a national 78%.
- On-time
- 71%
- arrived <15 min late
- Avg delay
- 21 min
- completed flights
- Cancelled
- 1.2%
- Flights/day
- 1.2
- last 12 months
- Duration
- 2h 6m
- scheduled
- Distance
- 667 mi
Best airline from IAH to STL
2 airlines flew this route regularly between 2024-06 and 2026-05.
| Airline | On-time | Avg delay | Cancelled | Flights |
|---|---|---|---|---|
| United Airlinesmost reliable | 72% | 20 min | 1.3% | 1,040 |
| SkyWest Airlines | 69% | 27 min | 0.0% | 150 |
Monthly on-time trend
Best time to fly from IAH to STL
Aim for departures around 1 p.m. (83% on-time); avoid 2 p.m. departures (67%).
By day of week
| Day | On-time | Avg delay |
|---|---|---|
| Monday | 68% | 24 min |
| Tuesdaybest | 79% | 11 min |
| Wednesday | 73% | 15 min |
| Thursday | 66% | 31 min |
| Friday | 71% | 22 min |
| Saturday | 72% | 19 min |
| Sunday | 71% | 22 min |
What causes delays on this route
Share of total delay minutes by cause, as reported by carriers to the US DOT.
- Late-arriving aircraft52%
- Airline operations33%
- National airspace system8%
- Weather7%
Frequently asked questions
- How often are flights from IAH to STL delayed?
- 29% of IAH–STL 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 21 minutes.
- Which airline is most reliable from IAH to STL?
- United Airlines has the best on-time record on this route at 72%, based on 1,040 flights. 2 airlines flew IAH–STL frequently enough to compare in this period.
- What is the best time of day to fly from IAH to STL?
- Departures around 1 p.m. have the best record (83% on-time), while departures around 2 p.m. have the worst (67%). As on most US routes, delays accumulate through the day, so earlier flights are generally safer.
- How long is the flight from IAH to STL?
- The scheduled IAH–STL flight time averages 2h 6m over 667 miles. Actual arrival times vary — flights on this route land 15+ minutes late 29% of the time.
- How often are IAH to STL 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 STL?
- June 2025 was the roughest month in this dataset, with only 40% of arrivals on time. The best was January 2026 at 88%. If your dates are flexible, that 48-point gap is worth planning around.
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Based on 1,190 flights, 2024-06–2026-05. Source: US DOT Bureau of Transportation Statistics. Updated 2026-07-01.