Carrier route record
WNMIA→BNA
Southwest Airlines · Miami to Nashville
- Flights
- 735
- Period
- July 2025 to June 2026
- Share of route
- 29%
- Carriers
- 5
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with Southwest Airlines.
Southwest on MIA to BNA sits in the middle of the pack with a C+. About seven flights in ten arrive on time by the DOT's definition, 6 points worse than the national rate of 77.6%. The late ones land about 55 minutes behind schedule. That rests on 735 flights, with a median arrival 2 minutes early.
The national on-time rate over the same period is 77.6%, so Southwest on MIA to BNA runs 6 points behind the country as a whole. Across a thousand flights that is about 64 extra late arrivals.
Key figures
On time
71.2%
Arrivals under 15 minutes late, of 728 completed flights
Avg delay
55 min
Across delayed arrivals only, not all flights
Cancelled
0.95%
National rate is 1.81%
Whole route
71.4%
Every carrier on MIA to BNA, 2,503 flights
These figures cover 735 flights between July 2025 and June 2026. The median arrival is 2 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
Southwest against every carrier on MIA to BNA
Southwest flew 735 of the 2,503 flights on MIA to BNA, about 29% of it. Its 71.2% on time is about level with the route as a whole at 71.4%. Ranked by on-time rate it is number four of five carriers on the route, where the range runs from Envoy at 90.3% to American at 66.5%. Three of those carriers flew fewer than 365 flights here, so treat their positions as rough.
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 |
|---|---|---|---|---|---|
| Envoy Airthin sample | 344 | 90.3% | 47 min | 1.16% | A |
| Spirit Airlinesthin sample | 66 | 75.0% | 102 min | 3.03% | B− |
| Republic Airwaysthin sample | 37 | 72.2% | 77 min | 2.70% | C |
| Southwest Airlines (this page) | 735 | 71.2% | 55 min | 0.95% | C+ |
| American Airlines | 1,321 | 66.5% | 76 min | 1.29% | C |
Departure window
When Southwest runs best on this route
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 50 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–8am147 flights94.5%
- 8am–11am90 flights92.1%
- 11am–2pm216 flights72.4%
- 2pm–5pm97 flights58.9%
- 5pm–8pm151 flights48.0%
- 8pm–5am34 flights44.1%
Scale runs 35% to 100%. Rows with fewer than 30 flights show a dash.
The 8pm–5am window is where this operation falls apart: 44.1% on time, against 94.5% 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 11am–2pm window is the busiest, with 216 flights scheduled in it.
Across the year
Southwest on MIA to BNA through the year
Delays peak in May, when the on-time rate falls to 50.0%. July is the strongest month at 89.7%. Moving a flexible trip across that boundary buys 40 points. May was the busiest month here, with 72 flights.
Across the week, Wednesday is the strongest day at 80.8% on time and Sunday the weakest at 61.2%. 20 points is a smaller lever than departure hour, but it is free.
Delay causes
Why Southwest runs late on this route
One category carries most of the weight here. Late-arriving aircraft accounts for 59% of the 11,000 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.
- 59%Late-arriving aircraft
- 26%Carrier
- 13%National Airspace System
- 2%Extreme weather
59% 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 11,000 reported delay minutes here, that single category outweighs weather by 24 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 11,488 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 94.5% on time here.
Cancellations sit at 0.95% against a national 1.81%, which is ordinary. Diversions add another 0.00%.
Connections and stage length
What a delay here costs
7.6% 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.
The 806 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 runs 72.6% on time across 735 flights, within about a point of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.
One caution: this is a thin sample. 735 flights over twelve months is enough to clear this site's floor but not enough to pin the rate down tightly, and a single bad week moves it by more than a point. Treat the grade as a rough reading.
What to do with this
Booking Southwest on MIA to BNA
Put together: treat all of this as provisional. 735 flights over twelve months is enough to clear this site's floor and not enough to be confident to better than a couple of points. The 71.2% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 728 completed flights over 12 months sit behind that.
Related
Where to go next
- MIA to BNA, every carrier
- Southwest on BNA to MIA, the return leg
- Envoy Air on MIA to BNA90.3%
- American Airlines on MIA to BNA66.5%
- Southwest Airlines network-wide record
- Miami International (MIA) delay statistics
- Nashville International (BNA) delay statistics
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.04 million flight records
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.