Seattle (SEA) to Houston (IAH): On-Time Performance
Data through July 2026
The calendar drives reliability on SEA–IAH. February 2026 flights landed on schedule 94% of the time, but June 2025 dropped to 63% — a gap of 31 points. Across the full period the route averages 79% on-time against a national 78%.
- On-time
- 79%
- arrived <15 min late
- Avg delay
- 13 min
- completed flights
- Cancelled
- 1.1%
- Flights/day
- 5.7
- last 12 months
- Duration
- 4h 23m
- scheduled
- Distance
- 1,874 mi
Best airline from SEA to IAH
2 airlines flew this route regularly between 2024-07 and 2026-07.
| Airline | On-time | Avg delay | Cancelled | Flights |
|---|---|---|---|---|
| United Airlinesmost reliable | 83% | 13 min | 1.1% | 2,639 |
| Alaska Airlines | 73% | 14 min | 1.0% | 1,794 |
Monthly on-time trend
Best time to fly from SEA to IAH
Aim for departures around 3 p.m. (95% on-time); avoid 11 a.m. departures (65%).
By day of week
| Day | On-time | Avg delay |
|---|---|---|
| Monday | 80% | 13 min |
| Tuesday | 80% | 11 min |
| Wednesdaybest | 84% | 9 min |
| Thursday | 78% | 14 min |
| Friday | 74% | 18 min |
| Saturday | 79% | 14 min |
| Sunday | 78% | 12 min |
What causes delays on this route
Share of total delay minutes by cause, as reported by carriers to the US DOT.
- Late-arriving aircraft30%
- Airline operations43%
- National airspace system25%
- Weather2%
Frequently asked questions
- How often are flights from SEA to IAH delayed?
- 21% of SEA–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 13 minutes.
- Which airline is most reliable from SEA to IAH?
- United Airlines has the best on-time record on this route at 83%, based on 2,639 flights. 2 airlines flew SEA–IAH frequently enough to compare in this period.
- What is the best time of day to fly from SEA to IAH?
- Departures around 3 p.m. have the best record (95% on-time), while departures around 11 a.m. have the worst (65%). As on most US routes, delays accumulate through the day, so earlier flights are generally safer.
- How long is the flight from SEA to IAH?
- The scheduled SEA–IAH flight time averages 4h 23m over 1,874 miles. Actual arrival times vary — flights on this route land 15+ minutes late 21% of the time.
- How often are SEA to IAH flights cancelled?
- 1.1% 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 SEA to IAH?
- June 2025 was the roughest month in this dataset, with only 63% of arrivals on time. The best was February 2026 at 94%. If your dates are flexible, that 31-point gap is worth planning around.
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Based on 4,433 flights, 2024-07–2026-07. Source: US DOT Bureau of Transportation Statistics. Updated 2026-09-28.