Carrier route record
WNSFO→BNA
Southwest Airlines · San Francisco to Nashville
- Flights
- 312
- Period
- September 2025 to August 2026
- Share of route
- 27%
- Carriers
- 2
Historical statistics for September 2025 to August 2026, not live status. For today’s flights, check with Southwest Airlines.
Southwest on SFO to BNA draws a D+. Roughly one flight in two arrives at least 15 minutes late, and the typical late arrival is about 50 minutes behind schedule. Build slack into anything you connect to. That rests on 312 flights, with a median arrival 9 minutes late.
The national on-time rate over the same period is 77.3%, so Southwest on SFO to BNA runs 19 points behind the country as a whole. Across a thousand flights that is about 189 extra late arrivals.
Key figures
On time
58.4%
Arrivals under 15 minutes late, of 310 completed flights
Avg delay
50 min
Across delayed arrivals only, not all flights
Cancelled
0.32%
National rate is 1.89%
Whole route
72.0%
Every carrier on SFO to BNA, 1,174 flights
These figures cover 312 flights between September 2025 and August 2026. Beyond the headline rate, 12.6% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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Carrier by carrier
Southwest against every carrier on SFO to BNA
Southwest flew 312 of the 1,174 flights on SFO to BNA, about 27% of it. Its 58.4% on time is 14 points worse than the route as a whole, which runs 72.0%. Ranked by on-time rate it is last of two carriers on the route, where the range runs from United at 77.0% to Southwest at 58.4%.
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 |
|---|---|---|---|---|---|
| United Airlines | 862 | 77.0% | 59 min | 0.46% | B+ |
| Southwest Airlines (this page)thin sample | 312 | 58.4% | 50 min | 0.32% | D+ |
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Departure window
When Southwest runs best on this route
Departure time is the single lever a traveller controls, and it moves the odds more than most people expect. Each bar below is the on-time rate for flights scheduled to leave inside that window, across 312 flights.
- 5am–8am10 flights—
- 8am–11am90 flights51.7%
- 11am–2pm32 flights59.4%
- 2pm–5pm—
- 5pm–8pm—
- 8pm–5am180 flights59.4%
Scale runs 45% to 65%. Rows with fewer than 30 flights show a dash.
The best window here is not the first bank but the 11am–2pm slot at 59.4% on time, ahead of 8am–11am at 51.7%. Where the curve peaks mid-day rather than at dawn, the constraint is usually congestion at one end rather than the aircraft's own rotation. The 8pm–5am window is the busiest, with 180 flights scheduled in it.
Across the year
Southwest on SFO to BNA through the year
- Jul–Sep 202530 flights36.7%
- Oct–Dec 202568 flights55.2%
- Jan–Mar 202661 flights80.0%
- Apr–Jun 202691 flights56.0%
- Jul–Sep 202662 flights54.8%
Scale runs 30% to 85%.
Monthly volumes are too low here to break the year into twelve reliable readings. What the twelve-month total says is 58.4% on time across 312 flights.
Southwest on SFO to BNA did not run the same all year. Its best quarter was Jan–Mar 2026 at 80.0% on time and its weakest Jul–Sep 2025 at 36.7%, a swing of 43 points on roughly 62 flights a quarter. The twelve-month rate averages over that, so if you are flying in a weak quarter the quarter's own figure is the better guide.
Across the week, Saturday is the strongest day at 90.2% on time and Friday the weakest at 44.7%, a spread of 46 points.
Arrival by arrival
How late Southwest on SFO to BNA runs when it is late
The 129 late arrivals split 46 under half an hour, 44 between 30 and 60 minutes, and 39 an hour or more.
- 15+ min early28 flights9.0%
- Within 15 min153 flights49.4%
- 15–29 min late46 flights14.8%
- 30–59 min late44 flights14.2%
- 1–2 hours late31 flights10.0%
- 2+ hours late8 flights2.6%
Scale runs 0% to 100%.
Share of 310 completed flights by arrival against schedule.
20 of 133 late departures made up the time and arrived on time, 15% of them. In the other direction, 16 flights left on time yet arrived 15 minutes late or more, so that delay built up after pushback: in the air, in a holding pattern or on the ground at BNA.
The worst days
Worst days for Southwest on SFO to BNA
The latest arrival of the period was on 15 July 2026, 3 hours 31 minutes behind schedule; most of its delay minutes were filed as a late-arriving aircraft. The same cause led on three of the five worst days.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 15 July 2026 | 3 hours 31 minutes | Late-arriving aircraft |
| 15 February 2026 | 2 hours 23 minutes | Late-arriving aircraft |
| 22 July 2026 | 2 hours 15 minutes | Carrier |
| 8 September 2025 | 2 hours 14 minutes | Late-arriving aircraft |
| 9 November 2025 | 2 hours 10 minutes | Carrier |
Delay causes
Why Southwest runs late on this route
Late-arriving aircraft accounts for 71% of the 6,465 delay minutes carriers reported here, and the remaining four split what is left.
- 71%Late-arriving aircraft
- 16%Carrier
- 12%National Airspace System
71% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 6,465 reported delay minutes here, that single category outweighs weather by 71 to one. The split is drawn from 6,465 reported delay minutes.
Cancellations are rare at 0.32%, below the national 1.89% 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
12.6% of arrivals land a full hour or more behind schedule, against 8.3% nationally. Ninety minutes is the honest minimum for a connection here, and two hours if the onward flight is on a separate ticket.
At 1,969 miles this is transcontinental flying, and long routes get a quiet structural advantage. Scheduled block time on a flight this length carries more padding in absolute minutes, so a twenty-minute late departure often still becomes an on-time arrival. Read the on-time rate here as slightly flattering next to a short-haul route with the same operational quality.
The return leg is a different operation and performs like one: it runs 49.2% on time across 312 flights, 9 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 9 points of difference.
One caution: this is a thin sample. 312 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 SFO to BNA
Put together: treat all of this as provisional. 312 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 58.4% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 310 completed flights over 12 months sit behind that.
Related
Where to go next
- SFO to BNA, every carrier
- Southwest on BNA to SFO, the return leg
- United Airlines on SFO to BNA77.0%
- Southwest Airlines network-wide record
- San Francisco International (SFO) delay statistics
- Nashville International (BNA) delay statistics
- Why the first flight of the morning is statistically safest
- How often a connection fails at the major US hubs
Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.