Carrier route record
WNDTW→BNA
Southwest Airlines · Detroit to Nashville
- Flights
- 846
- Period
- July 2025 to June 2026
- Share of route
- 35%
- Carriers
- 4
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with Southwest Airlines.
Southwest on DTW to BNA lands a B+, level with the national rate of 77.6%. Roughly one flight in four arrives 15 minutes late or worse, and those flights are late by roughly 40 minutes on average. That is a workable record, not a spotless one. That rests on 846 flights, with a median arrival 3 minutes early.
The US average over the same twelve months is 77.6%, so there is little to separate Southwest on DTW to BNA from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
77.7%
Arrivals under 15 minutes late, of 838 completed flights
Avg delay
39 min
Across delayed arrivals only, not all flights
Cancelled
0.71%
National rate is 1.81%
Whole route
78.7%
Every carrier on DTW to BNA, 2,417 flights
These figures cover 846 flights between July 2025 and June 2026. The median arrival is 3 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 DTW to BNA
Southwest flew 846 of the 2,417 flights on DTW to BNA, about 35% of it. Its 77.7% on time is about level with the route as a whole at 78.7%. Ranked by on-time rate it is number three of four carriers on the route, where the range runs from Delta at 79.5% to SkyWest at 72.7%. Two 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 |
|---|---|---|---|---|---|
| Delta Air Lines | 1,403 | 79.5% | 61 min | 1.85% | B |
| Spirit Airlinesthin sample | 146 | 77.9% | 73 min | 0.68% | B+ |
| Southwest Airlines (this page) | 846 | 77.7% | 39 min | 0.71% | B+ |
| SkyWest Airlinesthin sample | 22 | 72.7% | 56 min | 0.00% | 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 38 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–8am364 flights94.1%
- 8am–11am27 flights—
- 11am–2pm138 flights78.1%
- 2pm–5pm140 flights55.7%
- 5pm–8pm138 flights60.6%
- 8pm–5am39 flights56.4%
Scale runs 45% to 100%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 94.1% of the time, against 55.7% for the afternoon window. That is 38 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 5am–8am window is the busiest, with 364 flights scheduled in it.
Across the year
Southwest on DTW to BNA through the year
September is the best month on the calendar at 92.2% on time. Shoulder season thins the schedule and takes the summer weather with it, and the operation gets its margin back. May was the busiest month here, with 87 flights.
Across the week, Tuesday is the strongest day at 83.7% on time and Friday the weakest at 70.8%. 13 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 51% of the 7,278 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.
- 51%Late-arriving aircraft
- 25%Carrier
- 21%National Airspace System
- 2%Extreme weather
- 1%Security
51% 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 7,278 reported delay minutes here, that single category outweighs weather by 30 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 7,278 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 94.1% 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 costs
Badly late arrivals are rare here: only 3.7% land an hour or more behind schedule, against 8.1% nationally. Connections built on this flight are about as safe as US domestic connections get, though a cancelled flight still ignores every layover you give it.
At 456 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 is a different operation and performs like one: it runs 68.0% on time across 846 flights, 10 points below 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 10 points of difference.
One caution: this is a thin sample. 846 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 DTW to BNA
Put together: treat all of this as provisional. 846 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 77.7% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 838 completed flights over 12 months sit behind that.
Related
Where to go next
- DTW to BNA, every carrier
- Southwest on BNA to DTW, the return leg
- Delta Air Lines on DTW to BNA79.5%
- Spirit Airlines on DTW to BNA77.9%
- Southwest Airlines network-wide record
- Detroit Metropolitan Wayne County (DTW) 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.