San Francisco (SFO) to Houston (IAH): On-Time Performance
Data through July 2026
San Francisco (SFO) to Houston (IAH) effectively runs on two schedules. In September 2025, 92% of arrivals were on time; in December 2024 that fell to 72% — a 21-point seasonal swing. Across the full period the route averages 84% on-time against a national 78%.
- On-time
- 84%
- arrived <15 min late
- Avg delay
- 10 min
- completed flights
- Cancelled
- 0.7%
- Flights/day
- 9.9
- last 12 months
- Duration
- 3h 55m
- scheduled
- Distance
- 1,635 mi
Monthly on-time trend
Best time to fly from SFO to IAH
Aim for departures around 5 a.m. (96% on-time); avoid 10 a.m. departures (70%).
By day of week
| Day | On-time | Avg delay |
|---|---|---|
| Monday | 82% | 11 min |
| Tuesday | 86% | 8 min |
| Wednesdaybest | 88% | 7 min |
| Thursday | 84% | 10 min |
| Friday | 82% | 11 min |
| Saturday | 84% | 10 min |
| Sunday | 83% | 11 min |
What causes delays on this route
Share of total delay minutes by cause, as reported by carriers to the US DOT.
- Late-arriving aircraft35%
- Airline operations39%
- National airspace system25%
- Weather1%
Frequently asked questions
- How often are flights from SFO to IAH delayed?
- 16% of SFO–IAH flights arrived 15 or more minutes late (the US DOT definition of a delay) between 2024-07 and 2026-07. The average arrival delay across completed flights was 10 minutes.
- What is the best time of day to fly from SFO to IAH?
- Departures around 5 a.m. have the best record (96% on-time), while departures around 10 a.m. have the worst (70%). As on most US routes, delays accumulate through the day, so earlier flights are generally safer.
- How long is the flight from SFO to IAH?
- The scheduled SFO–IAH flight time averages 3h 55m over 1,635 miles. Actual arrival times vary — flights on this route land 15+ minutes late 16% of the time.
- How often are SFO to IAH flights cancelled?
- 0.7% of scheduled flights on this route were cancelled between 2024-07 and 2026-07, at or below the national rate of 1.6%.
- What is the worst month to fly from SFO to IAH?
- December 2024 was the roughest month in this dataset, with only 72% of arrivals on time. The best was September 2025 at 92%. If your dates are flexible, that 21-point gap is worth planning around.
Explore related pages
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Related guides
Based on 7,196 flights, 2024-07–2026-07. Source: US DOT Bureau of Transportation Statistics. Updated 2026-09-28.