Washington (IAD) to Houston (IAH): On-Time Performance
Data through July 2026
Washington (IAD) to Houston (IAH) effectively runs on two schedules. In February 2026, 94% of arrivals were on time; in July 2024 that fell to 63% — a 31-point seasonal swing. Across the full period the route averages 81% on-time against a national 78%. Morning departures also hold up better than evening ones (89% vs 72%), which matters most in the rough months.
- On-time
- 81%
- arrived <15 min late
- Avg delay
- 14 min
- completed flights
- Cancelled
- 0.8%
- Flights/day
- 5.1
- last 12 months
- Duration
- 3h 25m
- scheduled
- Distance
- 1,190 mi
Monthly on-time trend
Best time to fly from IAD to IAH
Aim for departures around 11 a.m. (95% on-time); avoid 4 p.m. departures (61%).
By day of week
| Day | On-time | Avg delay |
|---|---|---|
| Monday | 81% | 16 min |
| Tuesday | 83% | 13 min |
| Wednesday | 81% | 12 min |
| Thursday | 81% | 12 min |
| Friday | 81% | 16 min |
| Saturday | 79% | 16 min |
| Sundaybest | 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 aircraft26%
- Airline operations31%
- National airspace system33%
- Weather11%
Frequently asked questions
- How often are flights from IAD to IAH delayed?
- 19% of IAD–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 14 minutes.
- What is the best time of day to fly from IAD to IAH?
- Departures around 11 a.m. have the best record (95% on-time), while departures around 4 p.m. have the worst (61%). As on most US routes, delays accumulate through the day, so earlier flights are generally safer.
- How long is the flight from IAD to IAH?
- The scheduled IAD–IAH flight time averages 3h 25m over 1,190 miles. Actual arrival times vary — flights on this route land 15+ minutes late 19% of the time.
- How often are IAD to IAH flights cancelled?
- 0.8% 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 IAD to IAH?
- July 2024 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 3,868 flights, 2024-07–2026-07. Source: US DOT Bureau of Transportation Statistics. Updated 2026-09-28.