Carrier route record

WNBNA→DEN

Southwest Airlines · Nashville to Denver

Flights: 2,148
Period: July 2025 to June 2026
Share of route: 59%
Carriers: 3

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

Southwest on BNA to DEN sits in the middle of the pack with a C+. About seven flights in ten arrive on time by the DOT's definition, 5 points worse than the national rate of 77.6%. The late ones land roughly 50 minutes behind schedule. That rests on 2,148 flights, with a median arrival 1 minute early.

The national on-time rate over the same period is 77.6%, so Southwest on BNA to DEN runs 5 points behind the country as a whole. Across a thousand flights that is about 53 extra late arrivals.

On time

72.3%

Arrivals under 15 minutes late, of 2,136 completed flights

Avg delay

51 min

Across delayed arrivals only, not all flights

Cancelled

0.42%

National rate is 1.81%

Whole route

74.9%

Every carrier on BNA to DEN, 3,665 flights

These figures cover 2,148 flights between July 2025 and June 2026. On-time means an arrival less than 15 minutes after the scheduled gate time, the same threshold the Department of Transportation uses in its own reports. Cancelled and diverted flights are excluded from the on-time rate and counted separately, which is why the cancellation column matters on its own.

Carrier by carrier

Southwest against every carrier on BNA to DEN

Southwest flew 2,148 of the 3,665 flights on BNA to DEN, most of the route. Its 72.3% on time is 3 points worse than the route as a whole, which runs 74.9%. Ranked by on-time rate it is last of three carriers on the route, where the range runs from United at 79.3% to Southwest at 72.3%. One 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.

On-time performance by carrier on BNA to DEN
Airline	Flights	On time	Avg delay	Cancelled	Grade
United Airlines	1,168	79.3%	77 min	0.77%	B+
Frontier Airlinesthin sample	349	76.1%	87 min	1.43%	B
Southwest Airlines (this page)	2,148	72.3%	51 min	0.42%	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 42 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–8am533 flights93.8%
8am–11am247 flights85.0%
11am–2pm317 flights72.2%
2pm–5pm391 flights57.7%
5pm–8pm354 flights51.4%
8pm–5am306 flights67.8%

Scale runs 45% to 100%. Rows with fewer than 30 flights show a dash.

The 5pm–8pm window is where this operation falls apart: 51.4% on time, against 93.8% 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 5am–8am window is the busiest, with 533 flights scheduled in it.

Across the year

Southwest on BNA to DEN through the year

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

June is the worst month at 52.8% on time, 33 points below November, the best at 85.3%. 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. July was the busiest month here, with 219 flights.

Across the week, Saturday is the strongest day at 79.3% on time and Thursday the weakest at 66.3%. 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 43% of the 30,000 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
43%
National Airspace System
30%
Carrier
24%
Extreme weather
3%
Security
0%

43% 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 30,000 reported delay minutes here, that single category outweighs weather by 14 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 30,304 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 93.8% on time here.

Cancellations are rare at 0.42%, 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

7.5% 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 1,013 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 2,142 flights, within half a point 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 2,148 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 BNA to DEN

Put together: the calendar is the biggest lever here, not the carrier or the hour. November runs 85.3% on time and June 52.8%, a swing of 33 points. If the dates move at all, move them out of June before you think about anything else. 2,136 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