According to PlainFlights' airport traffic ranking (BTS On-Time Performance total flights), Houston, TX (IAH) ranks #17 of 382 tracked US airports by total flights (most flights = #1). Houston, TX posts below-median on-time performance among the 382 tracked U.S. airports, as one of the busiest U.S. airports.
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IAH on-time rate vs. the national average
Ahead of the U.S. average across all 382 tracked airports.
Delay Cause Breakdown
Top delay cause: Carrier.
Total delay minutes: 9,961,952.
Late Aircraft34.9% (3,475,885 min)
Carrier38.4% (3,821,797 min)
NAS (National Aviation System)18.1% (1,806,413 min)
Weather8.6% (852,957 min)
Security0.0% (4,900 min)
IAH - seasonal on-time pattern
Best: September (92.8%) · worst: July (86.4%)
IAH - on-time rate by year
2020–2025, year-over-year trend.
IAH - taxi-out and taxi-in (monthly)
Average taxi-out 20.2 min · taxi-in 10.9 min over the last 24 reported months (U.S. airport mean taxi-out ≈ 16.4 min).
IAH's average taxi-out (20.2 min) runs longer than the recent U.S. airport mean (~16.4 min). The heaviest month in this window is May 2025 at 21.7 min; the lightest is August 2024 at 18.7 min.
Two PlainFlights-derived comparison paths for Houston, TX, both outside Texas so the neighborhoods are not same-state geography. Axes stay disjoint: volume peers exclude the on-time peer set. Same-state compare stays below.
The standout signal at Houston, TX is traffic scale: 1,404,392 BTS flights (2020–2025) place it #17 of 382 by book size. That busy-book footprint sits beside a 81.6% on-time rate (2.6 pts above the 79% national flight-weighted average), 258,419 delayed departures, and 15,858 cancellations (1.13% of the book).
Delay minutes concentrate in Carrier (34.9% late-aircraft, 38.4% carrier, 18.1% NAS, 8.6% weather, 0.0% security). As a busy airport, that mix matters more for connection planning than for a thin schedule.
On the multi-year calendar, IAH is strongest in September (92.8% on-time) and weakest in July (86.4%), a 6.4-point swing. Volume peaks in March (~21,723 flights/month). The busiest connecting route is to DFW (Dallas/Fort Worth) at 76.6% on-time. Field definitions: on-time performance explained.
Houston, TX vs. the national on-time distribution
On-time rate among all 382 tracked U.S. airports
81.6%Top 71%higher than 29% of 382 airports
Houston, TX
60%95%
U.S. airports by on-time rate, bucketed by value
Each bar is a band; taller bars hold more airports. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count and share, and where it sits relative to this entry.
Data Source: Bureau of Transportation Statistics (BTS), On-Time Performance Data (2020–2025).
Statistics reflect cumulative performance across all available reporting periods. On-time rates exclude cancelled and diverted flights.
IAH's on-time book sits in the slower half of the BTS set; check the delay mix and the worst month before treating the headline as typical.
Check the busiest route from IAH before you book a connection. See top routes →
Travel in September rather than July if your dates are flexible. Seasonal patterns →
Build extra connection buffer when taxi-out spikes. May 2025 averaged 21.7 min. Taxi times →
On-time rate reflects the BTS historical average across all reporting carriers at this airport, not any single flight or airline.
Frequently Asked Questions
What is Houston, TX's on-time rate?
Houston, TX (IAH) has a 81.6% on-time rate across 1,404,392 BTS-tracked flights (2020-2025), 2.6 pts above the 79% national flight-weighted average; that places it in roughly the below-median on-time performance.
How does IAH rank among U.S. airports by traffic volume?
Houston, TX ranks #17 of 382 tracked US airports by total BTS flights (most flights = #1), making it one of the busiest U.S. airports.
What's the most common cause of delays at Houston, TX?
Carrier is the leading delay cause at IAH, accounting for 38.4% of delay minutes. The full breakdown: 34.9% late-aircraft, 38.4% carrier, 18.1% NAS/air-traffic-control, 8.6% weather, and 0.0% security.
When is the best time to fly through Houston, TX?
September is historically IAH's strongest month at 92.8% on-time, while July is the weakest at 86.4%, a 6.4-point swing across the BTS historical record.
Data sourced from U.S. Department of Transportation Bureau of Transportation Statistics (BTS) On-Time Performance data. See our methodology for details. Retrieved and formatted by PlainFlights