Best Time to Fly IAH to SEA: On-Time Stats by Hour & Airline
George Bush Intercontinental/Houston → Seattle/Tacoma International
Data through July 2026 · Last updated October 18, 2026
Over the last 12 months, 79.0% of Houston (IAH) to Seattle (SEA) flights arrived on time (2,090 scheduled flights). That is 1.4 points above the national average of 77.6%.
Among 2 airlines, Alaska Airlines led with 80.3% on time and United Airlines was last with 78.1%.
Over 24 months, Tuesday was the most reliable day (83% on time) and June the worst month (68%).
The cancellation rate was 0.4% (US average 1.8%).
IAH to SEA 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 |
|---|---|---|---|---|
| Alaska Airlines | 80.3% | 51 min | 0.6% | 852 |
| United Airlines | 78.1% | 53 min | 0.2% | 1,238 |
80%+ good 70–79.9% fair <70% poor
Best time of day to fly IAH to SEA
On-time arrival % by scheduled departure hour (local time), 4,186 flights over 24 months.
Show the numbers
| Departure hour | On time | Cancelled | Flights |
|---|---|---|---|
| 6am–7am | 89.9% | 1.2% | 322 |
| 7am–8am | 85.5% | 1.4% | 504 |
| 8am–9am | 86.5% | 0.0% | 222 |
| 9am–10am | 84.2% | 0.7% | 572 |
| 10am–11am | 80.3% | 0.0% | 274 |
| 11am–12pm | 83.3% | 0.0% | 36 |
| 2pm–3pm | 85.2% | 0.0% | 115 |
| 4pm–5pm | 78.6% | 0.3% | 625 |
| 5pm–6pm | 76.4% | 1.8% | 57 |
| 6pm–7pm | 67.6% | 0.9% | 451 |
| 7pm–8pm | 66.4% | 1.3% | 750 |
| 8pm–9pm | 70.2% | 0.0% | 239 |
| 9pm–10pm | Limited data | 19 | |
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 SEA
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) | 72.7% | -7.3 pts | 0.0% | 66 |
| Christmas & New Year (Dec 20 - Jan 3) | 77.9% | -2.1 pts | 0.6% | 165 |
| Summer peak (Jun 15 - Aug 15) | 71.7% | -8.4 pts | 1.6% | 944 |
| All other days | 80.0% | — | 0.5% | 3,011 |
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).