Route reliability record
IAH→BNA
Houston to Nashville
- Flights
- 1,405
- Period
- July 2025 to June 2026
- Distance
- 657 mi
- Carriers
- 3
This route sits in the middle of the pack with a C+. About seven flights in ten arrive on time by the DOT's definition, 5 points worse than the national rate of 77.6%. The late ones land about an hour behind schedule. That rests on 1,405 IAH to BNA flights, of which United Airlines flew 998 at 73.9% on time.
Best time to fly IAH to BNA: a 5am–8am departure, ideally on a Wednesday. Flights in that window arrived on time 86.3% of the time and Wednesday flights 78.6%, against 72.2% for the route overall.
The national on-time rate over the same period is 77.6%, so this route runs 5 points behind the country as a whole. Across a thousand flights that is about 54 extra late arrivals.
Key figures
On time
72.2%
Arrivals under 15 minutes late, of 1,390 completed flights
Avg delay
66 min
Across delayed arrivals only, not all flights
Cancelled
0.71%
National rate is 1.81%
Best carrier
United
73.9% on time across 998 flights
These figures cover 1,405 flights between July 2025 and June 2026. Beyond the headline rate, 9.0% of arrivals land a full hour or more behind schedule. That is the number that wrecks a connection, and it is not visible in an on-time percentage alone.
Carrier by carrier
Which airline is most reliable on IAH to BNA
The two carriers here are closely matched: 5 points separate the best from the worst. At that spread, schedule and price are better tie-breakers than reliability. Sample sizes are shown so you can see which rows are worth weighing.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| United Airlines | 998 | 73.9% | 61 min | 0.50% | C+ |
| SkyWest Airlines | 394 | 69.0% | 77 min | 1.02% | C |
| Spirit Airlinesthin sample | 13 | 41.7% | 39 min | 7.69% | F− |
No carrier stands out. United tops the table at 73.9%, 5 points clear of the bottom, which is inside the range this kind of sample moves year to year.
Flight by flight
Flights on IAH to BNA
The flight numbers below flew this route at least 250 times in the period, busiest first. Each has its own record, with its schedule and delay causes.
Best ways to make this trip
The most reliable ways to fly Houston to Nashville
Every airline on this route and on the routes between nearby airports, ranked by how often a scheduled flight actually operated and arrived on time. 1 of the top 3 use a different airport at one end.
| Option | Airline | Success | On time | Cancelled | Best departure | Most punctual flight |
|---|---|---|---|---|---|---|
| 1. HOU → BNAHouston to Nashville | Southwest Airlines | 77.2% | 77.7% | 0.61% | 5am–8am, Tue | — |
| 2. IAH → BNAHouston to Nashville | United Airlines | 73.5% | 73.9% | 0.50% | 5am–8am, Wed | UA 2174 07:35 |
| 3. IAH → BNAHouston to Nashville | SkyWest Airlines | 68.3% | 69.0% | 1.02% | 5pm–8pm, Wed | OO 4785 18:05 |
Success is the share of scheduled flights that operated and arrived less than 15 minutes late, so a cancelled flight counts against it. “(route)” means the best time comes from every carrier on the route rather than this airline alone.
Departure window
The best time of day to leave
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 21 points, against 5 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am266 flights86.3%
- 8am–11am—
- 11am–2pm199 flights75.5%
- 2pm–5pm363 flights68.1%
- 5pm–8pm361 flights68.3%
- 8pm–5am216 flights65.4%
Scale runs 55% to 90%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 86.3% of the time, against 65.4% for the overnight window. That is 21 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 2pm–5pm window is the busiest, with 363 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 27 points from best month to worst, which is wide. An annual average tells you very little about the week you are actually flying, so read the strip rather than the headline if your dates are fixed.
July is the worst month at 60.9% on time, 27 points below January, the best at 87.4%. Summer afternoon convection and peak-season schedules land on the same weeks every year, so this is a pattern you can book around rather than a run of bad luck. March was the busiest month here, with 142 flights.
Across the week, Wednesday is the strongest day at 78.6% on time and Friday the weakest at 67.4%. 11 points is a smaller lever than departure hour, but it is free.
Delay causes
Why this route gets delayed
Carriers report a reason for every delay minute they cause, in five DOT categories. The split below is by minutes, not by number of flights, so a handful of very long weather delays weighs as much as many short ones. It covers 25,000 reported delay minutes.
- 35%Late-arriving aircraft
- 31%Carrier
- 25%National Airspace System
- 10%Extreme weather
35% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. That is a cascade, and cascades start small and grow through the day. Across 25,000 reported delay minutes here, that single category outweighs weather by 4 to one. It is the strongest argument for booking the first departure of the morning, when the aircraft has been sitting at the gate overnight with nothing to inherit. The split is drawn from 25,289 reported delay minutes.
The practical consequence: the 5am–8am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 86.3% on time here.
Cancellations are rare at 0.71%, below the national 1.81% and low enough to earn the plus on the grade. Roughly one flight in 100 is called off; the risk here is arriving late, not not arriving.
Connections and stage length
What a delay here actually costs
For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 9.0% of arrivals land a full hour or more behind schedule, against 8.1% nationally. A 45-minute layover does not survive that, and no amount of walking quickly changes it. Ninety minutes is the honest minimum here, and two hours if the onward flight is on a separate ticket.
The 657 miles between these two airports put this in the middle of the US network, around two and a half to three hours of block time. That is enough cruise to absorb a ten-minute late pushback and not enough to absorb thirty. It is also long enough that the aircraft usually flies three or four legs a day rather than six, which slows how fast delay compounds.
The return leg is a different operation and performs like one: it runs 82.7% on time across 1,405 flights, 11 points above this direction. Departure banks, aircraft rotations and the congestion at each end all differ, so scoring the two directions together would average away a real 11 points of difference.
The sample behind these figures is 1,405 flights, enough that the headline rate is stable to within roughly a point. The hour-block and month splits divide that further, so read the thinner bars with more caution than the headline.
Work out the risk of missing a connection in BNA after this flight
What to do with this
Booking this route
Put together: the calendar is the biggest lever here, not the carrier or the hour. January runs 87.4% on time and July 60.9%, a swing of 27 points. If the dates move at all, move them out of July before you think about anything else. 1,390 completed flights over 12 months sit behind that.
Common questions
IAH to BNA questions
How often is IAH to BNA delayed?
Roughly one flight in four arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 27.8% of the 1,405 flights in this analysis, against 22.4% nationally. Delayed flights are late by about an hour on average.
Which airline is most reliable on IAH to BNA?
United Airlines leads at 73.9% on time across 998 flights. SkyWest Airlines is at the other end on 69.0%, a gap of 5 points. Sample size matters as much as the percentage: a rate built from a few hundred flights moves around far more than one built from ten thousand.
What time of day has the fewest delays on IAH to BNA?
The 5am–8am departure window is the strongest at 86.3% on time. The 8pm–5am window is the weakest at 65.4%, 21 points behind. Later departures inherit delays from earlier flights the same aircraft has already flown, which is why the curve slopes the way it does.
How bad are July delays on IAH to BNA?
July is the weakest month at 60.9% on time, compared with 87.4% in January. Across the year that is 27 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.
Related
Where to go next
- BNA to IAH — the return legseparate record
- George Bush Intercontinental (IAH) delay statistics
- Nashville International (BNA) delay statistics
- United Airlines on IAH to BNA73.9%
- SkyWest Airlines on IAH to BNA69.0%
- IAH to ORD, a related route74.8%
- ORD to BNA, a related route68.6%
- IAH to DFW, a related route75.0%
- United Airlines on-time record73.9%
- SkyWest Airlines on-time record69.0%
- Spirit Airlines on-time record41.7%
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.04 million flight records
Direction matters. IAH to BNA and BNA to IAH are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
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Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.