Houston (IAH) to San Francisco (SFO): On-Time Performance
Data through May 2026
The calendar drives reliability on IAH–SFO. September 2025 flights landed on schedule 89% of the time, but June 2025 dropped to 64% — a gap of 26 points. Across the full period the route averages 79% on-time against a national 78%. Morning departures also hold up better than evening ones (86% vs 71%), which matters most in the rough months.
- On-time
- 79%
- arrived <15 min late
- Avg delay
- 15 min
- completed flights
- Cancelled
- 0.8%
- Flights/day
- 9.8
- last 12 months
- Duration
- 4h 17m
- scheduled
- Distance
- 1,635 mi
Monthly on-time trend
Best time to fly from IAH to SFO
Aim for departures around 5 a.m. (97% on-time); avoid 8 p.m. departures (63%).
By day of week
| Day | On-time | Avg delay |
|---|---|---|
| Monday | 76% | 19 min |
| Tuesdaybest | 86% | 10 min |
| Wednesday | 78% | 17 min |
| Thursday | 78% | 14 min |
| Friday | 80% | 15 min |
| Saturday | 82% | 13 min |
| Sunday | 75% | 20 min |
What causes delays on this route
Share of total delay minutes by cause, as reported by carriers to the US DOT.
- Late-arriving aircraft32%
- Airline operations32%
- National airspace system29%
- Weather7%
Frequently asked questions
- How often are flights from IAH to SFO delayed?
- 21% of IAH–SFO 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 15 minutes.
- What is the best time of day to fly from IAH to SFO?
- Departures around 5 a.m. have the best record (97% on-time), while departures around 8 p.m. have the worst (63%). As on most US routes, delays accumulate through the day, so earlier flights are generally safer.
- How long is the flight from IAH to SFO?
- The scheduled IAH–SFO flight time averages 4h 17m over 1,635 miles. Actual arrival times vary — flights on this route land 15+ minutes late 21% of the time.
- How often are IAH to SFO flights cancelled?
- 0.8% 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 SFO?
- June 2025 was the roughest month in this dataset, with only 64% of arrivals on time. The best was September 2025 at 89%. If your dates are flexible, that 26-point gap is worth planning around.
Explore related pages
More routes from IAH
Based on 6,867 flights, 2024-06–2026-05. Source: US DOT Bureau of Transportation Statistics. Updated 2026-07-01.