Route reliability record
BNA→STL
Nashville to St. Louis
- Flights
- 1,274
- Period
- July 2025 to June 2026
- Distance
- 272 mi
- Carriers
- 1
This route lands a B+, 3 points better than the national rate of 77.6%. About one flight in five arrives 15 minutes late or worse, and those flights are late by roughly 50 minutes on average. That is a workable record, not a spotless one. That rests on 1,274 BNA to STL flights, with a median arrival 8 minutes early.
Best time to fly BNA to STL: a 5am–8am departure, ideally on a Saturday. Flights in that window arrived on time 95.5% of the time and Saturday flights 88.3%, against 80.2% for the route overall.
The US average over the same twelve months is 77.6%, so there is little to separate this route from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
80.2%
Arrivals under 15 minutes late, of 1,262 completed flights
Avg delay
51 min
Across delayed arrivals only, not all flights
Cancelled
0.94%
National rate is 1.81%
Best carrier
Southwest
80.2% on time across 1,274 flights
These figures cover 1,274 flights between July 2025 and June 2026. The median arrival is 8 minutes early, which is the part an average hides: most flights here are fine, and the on-time rate is decided by a tail of badly late ones. On-time means under 15 minutes late, the DOT's own threshold.
Carrier by carrier
Which airline is most reliable on BNA to STL
Only one carrier clears this site's 365-flight floor here, so there is no comparison to draw. The table below is the full picture.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Southwest Airlines | 1,274 | 80.2% | 51 min | 0.94% | B+ |
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 29 points, against half a point between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am267 flights95.5%
- 8am–11am100 flights94.9%
- 11am–2pm205 flights79.7%
- 2pm–5pm101 flights77.2%
- 5pm–8pm292 flights66.8%
- 8pm–5am309 flights76.1%
Scale runs 60% to 100%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 95.5% of the time, against 66.8% for the evening window. That is 29 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 8pm–5am window is the busiest, with 309 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.
Delays peak in May, when the on-time rate falls to 65.5%. January is the strongest month at 92.5%. Moving a flexible trip across that boundary buys 27 points. October was the busiest month here, with 119 flights.
Across the week, Saturday is the strongest day at 88.3% on time and Monday the weakest at 72.4%. 16 points is a smaller lever than departure hour, but it is free.
Delay causes
Why this route gets delayed
One category carries most of the weight here. Late-arriving aircraft accounts for 68% of the 13,000 delay minutes carriers reported, and the remaining four split what is left. The split is by minutes rather than by flights, so a few very long delays count for as much as many short ones.
- 68%Late-arriving aircraft
- 24%Carrier
- 5%National Airspace System
- 3%Extreme weather
- 0%Security
68% 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 13,000 reported delay minutes here, that single category outweighs weather by 26 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 12,851 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 95.5% on time here.
Cancellations sit at 0.94% against a national 1.81%, which is ordinary. Diversions add another 0.00%.
Connections and stage length
What a delay here actually costs
5.8% of arrivals land an hour or more late, close to the national 8.1%. That is the figure that decides a connection, and it says a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last roughly 50 minutes, which a normal layover absorbs.
At 272 miles this is a short hop, and stage length matters more than it looks. A flight this short spends under two hours in the air, which leaves almost nothing to claw back a late pushback with. Delay here is decided on the ground, in the turn, which is why the 5am–8am window matters as much as it does.
The return leg runs 82.8% on time across 1,275 flights, within 3 points of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.
The sample behind these figures is 1,274 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 STL 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 92.5% on time and May 65.5%, a swing of 27 points. If the dates move at all, move them out of May before you think about anything else. 1,262 completed flights over 12 months sit behind that.
Common questions
BNA to STL questions
How often is BNA to STL delayed?
About one flight in five arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 19.8% of the 1,274 flights in this analysis, against 22.4% nationally. Delayed flights are late by roughly 50 minutes on average.
How reliable is BNA to STL compared with the rest of the country?
80.2% of flights arrive on time here against a national 77.6%, a difference of 3 points in its favour. That is worth a B+ on this site's grading scale.
What time of day has the fewest delays on BNA to STL?
The 5am–8am departure window is the strongest at 95.5% on time. The 5pm–8pm window is the weakest at 66.8%, 29 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 May delays on BNA to STL?
May is the weakest month at 65.5% on time, compared with 92.5% 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
- STL to BNA — the return legseparate record
- Nashville International (BNA) delay statistics
- St. Louis Lambert International (STL) delay statistics
- BNA to ORD, a related route70.4%
- ATL to STL, a related route82.4%
- BNA to DCA, a related route73.3%
- Southwest Airlines on-time record80.2%
- 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. BNA to STL and STL to BNA 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.