Route reliability record
STL→BNA
St. Louis to Nashville
- Flights
- 1,275
- Period
- July 2025 to June 2026
- Distance
- 272 mi
- Carriers
- 1
This route lands a B+, 5 points better than the national rate of 77.6%. About one flight in six arrives 15 minutes late or worse, and those flights are late by about 55 minutes on average. That is a workable record, not a spotless one. That rests on 1,275 STL to BNA flights, with a median arrival 7 minutes early.
Best time to fly STL to BNA: a 5am–8am departure, ideally on a Wednesday. Flights in that window arrived on time 95.8% of the time and Wednesday flights 86.9%, against 82.8% for the route overall.
Set against the rest of the country, this route's record is 5 points better than the US average of 77.6%. That gap is worth roughly 52 fewer late arrivals for every thousand flights.
Key figures
On time
82.8%
Arrivals under 15 minutes late, of 1,265 completed flights
Avg delay
54 min
Across delayed arrivals only, not all flights
Cancelled
0.63%
National rate is 1.81%
Best carrier
Southwest
82.8% on time across 1,275 flights
These figures cover 1,275 flights between July 2025 and June 2026. The median arrival is 7 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 STL to BNA
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 | 1,275 | 82.8% | 54 min | 0.63% | 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 37 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–8am240 flights95.8%
- 8am–11am209 flights91.3%
- 11am–2pm249 flights87.9%
- 2pm–5pm219 flights75.6%
- 5pm–8pm280 flights73.0%
- 8pm–5am78 flights59.0%
Scale runs 50% to 100%. Rows with fewer than 30 flights show a dash.
The 8pm–5am window is where this operation falls apart: 59.0% on time, against 95.8% for the 5am–8am slot. By evening the aircraft flying these rotations have absorbed a full day of small delays and there is no slack left to recover in. The 5pm–8pm window is the busiest, with 280 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 22 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 72.0% on time, 22 points below September, the best at 93.5%. 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. October was the busiest month here, with 119 flights.
Across the week, Wednesday is the strongest day at 86.9% on time and Monday the weakest at 74.7%. 12 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 62% of the 12,000 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.
- 62%Late-arriving aircraft
- 24%Carrier
- 12%National Airspace System
- 2%Extreme weather
62% 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 12,000 reported delay minutes here, that single category outweighs weather by 27 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 11,847 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 95.8% on time here.
Cancellations are rare at 0.63%, 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
5.0% 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 about 55 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 80.2% on time across 1,274 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 1,275 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. September runs 93.5% on time and July 72.0%, a swing of 22 points. If the dates move at all, move them out of July before you think about anything else. 1,265 completed flights over 12 months sit behind that.
Common questions
STL to BNA questions
How often is STL to BNA delayed?
About one flight in six arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 17.2% of the 1,275 flights in this analysis, against 22.4% nationally. Delayed flights are late by about 55 minutes on average.
How reliable is STL to BNA compared with the rest of the country?
82.8% of flights arrive on time here against a national 77.6%, a difference of 5 points in its favour. That is worth a B+ on this site's grading scale.
What time of day has the fewest delays on STL to BNA?
The 5am–8am departure window is the strongest at 95.8% on time. The 8pm–5am window is the weakest at 59.0%, 37 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 STL to BNA?
July is the weakest month at 72.0% on time, compared with 93.5% in September. Across the year that is 22 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 STL — the return legseparate record
- St. Louis Lambert International (STL) delay statistics
- Nashville International (BNA) delay statistics
- STL to ATL, a related route85.3%
- ORD to BNA, a related route68.6%
- STL to DEN, a related route74.9%
- Southwest Airlines on-time record82.8%
- 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. STL to BNA and BNA to STL 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.