Carrier route record

WNAUS→BNA

Southwest Airlines · Austin to Nashville

Flights: 2,004
Period: July 2025 to June 2026
Share of route: 67%
Carriers: 2

Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with Southwest Airlines.

Southwest on AUS to BNA lands a B+, 2 points worse than the national rate of 77.6%. About one flight in four 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 2,004 flights, with a median arrival 2 minutes early.

The US average over the same twelve months is 77.6%, so there is little to separate Southwest on AUS to BNA from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.

On time

76.0%

Arrivals under 15 minutes late, of 1,987 completed flights

Avg delay

49 min

Across delayed arrivals only, not all flights

Cancelled

0.70%

National rate is 1.81%

Whole route

76.0%

Every carrier on AUS to BNA, 3,013 flights

These figures cover 2,004 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 AUS to BNA

Southwest flew 2,004 of the 3,013 flights on AUS to BNA, most of the route. Its 76.0% on time is about level with the route as a whole at 76.0%. Ranked by on-time rate it is last of two carriers on the route, where the range runs from SkyWest at 76.1% to Southwest at 76.0%.

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.

On-time performance by carrier on AUS to BNA
Airline	Flights	On time	Avg delay	Cancelled	Grade
SkyWest Airlines	1,009	76.1%	92 min	0.50%	B+
Southwest Airlines (this page)	2,004	76.0%	49 min	0.70%	B+

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 34 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–8am363 flights96.1%
8am–11am297 flights88.9%
11am–2pm407 flights79.0%
2pm–5pm389 flights61.9%
5pm–8pm342 flights63.1%
8pm–5am206 flights64.0%

Scale runs 55% to 100%. Rows with fewer than 30 flights show a dash.

Book the early departure. Flights leaving between 5am–8am arrive on time 96.1% of the time, against 61.9% for the afternoon window. That is 34 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 11am–2pm window is the busiest, with 407 flights scheduled in it.

Across the year

Southwest on AUS to BNA through the year

Darker means more delays. Figures are on-time percentages.January best, June worst

June is the worst month at 59.5% on time, 32 points below January, the best at 91.2%. 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 196 flights.

Across the week, Tuesday is the strongest day at 81.9% on time and Monday the weakest at 72.7%. 9 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 55% of the 23,000 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.

Late-arriving aircraft
55%
Carrier
26%
National Airspace System
16%
Extreme weather
2%
Security
0%

55% 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 23,000 reported delay minutes here, that single category outweighs weather by 28 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 23,330 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 96.1% on time here.

Cancellations are rare at 0.70%, 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

6.0% 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 roughly 50 minutes, which a normal layover absorbs.

The 756 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 is a different operation and performs like one: it runs 79.9% on time across 2,016 flights, 4 points above 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 4 points of difference.

The sample behind these figures is 2,004 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.

What to do with this

Booking Southwest on AUS to BNA

Put together: the calendar is the biggest lever here, not the carrier or the hour. January runs 91.2% on time and June 59.5%, a swing of 32 points. If the dates move at all, move them out of June before you think about anything else. 1,987 completed flights over 12 months sit behind that.

Where to go next

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.

Key figures