Best Time to Fly IAH to SFO: On-Time Stats by Hour & Airline
George Bush Intercontinental/Houston → San Francisco International
Data through July 2026 · Last updated October 18, 2026
Over the last 12 months, 78.1% of Houston (IAH) to San Francisco (SFO) flights arrived on time (3,598 scheduled flights). That is 0.5 points above the national average of 77.6%.
United Airlines was the only reporting airline with regular flights on this route.
September has been the best month (88% on time) and Monday the weakest day of the week (73%).
0.5% of flights were cancelled, versus 1.8% nationally.
IAH to SFO on-time performance by airline
Last 12 months. Airlines with fewer than 30 completed flights are marked “limited data”.
| Airline | On time | Avg delay when late | Cancelled | Flights |
|---|---|---|---|---|
| United Airlines | 78.1% | 63 min | 0.5% | 3,598 |
80%+ good 70–79.9% fair <70% poor
Best time of day to fly IAH to SFO
On-time arrival % by scheduled departure hour (local time), 6,915 flights over 24 months.
Show the numbers
| Departure hour | On time | Cancelled | Flights |
|---|---|---|---|
| 12am–1am | Limited data | 1 | |
| 5am–6am | 97.7% | 0.3% | 565 |
| 6am–7am | 96.8% | 0.0% | 123 |
| 7am–8am | 88.1% | 0.6% | 725 |
| 8am–9am | 72.0% | 0.0% | 125 |
| 9am–10am | 72.5% | 1.3% | 387 |
| 10am–11am | 74.4% | 0.9% | 343 |
| 11am–12pm | Limited data | 3 | |
| 12pm–1pm | 81.7% | 0.1% | 722 |
| 1pm–2pm | Limited data | 6 | |
| 2pm–3pm | 84.0% | 0.4% | 547 |
| 3pm–4pm | 73.1% | 0.3% | 381 |
| 4pm–5pm | 78.5% | 0.7% | 558 |
| 5pm–6pm | 78.2% | 0.9% | 218 |
| 6pm–7pm | 69.4% | 0.8% | 719 |
| 7pm–8pm | 61.1% | 0.0% | 240 |
| 8pm–9pm | 63.0% | 0.4% | 510 |
| 9pm–10pm | 77.3% | 1.0% | 678 |
| 10pm–11pm | 68.3% | 1.6% | 61 |
| 11pm–12am | Limited data | 3 | |
Best day of the week
24 months, by day of departure.
Best month to fly
24 months, by calendar month.
Holiday travel on IAH to SFO
On-time arrivals during holiday periods compared with all other days, last 24 months.
| Period | On time | vs other days | Cancelled | Flights |
|---|---|---|---|---|
| Thanksgiving week (Tue before to Mon after) | 84.0% | +3.3 pts | 0.0% | 131 |
| Christmas & New Year (Dec 20 - Jan 3) | 65.5% | -15.2 pts | 1.8% | 286 |
| Summer peak (Jun 15 - Aug 15) | 70.5% | -10.2 pts | 0.3% | 1,194 |
| All other days | 80.7% | — | 0.6% | 5,304 |
Monthly on-time trend
On-time arrival % each month, with the 12-month US average for reference.
What causes delays on this route
Share of reported delay minutes, last 12 months (BTS cause categories).