Route reliability record

DEN→BNA

Denver to Nashville

Flights: 3,658
Period: July 2025 to June 2026
Distance: 1,013 mi
Carriers: 3

This route sits in the middle of the pack with a C+. Close to three flights in four arrive on time by the DOT's definition, 3 points worse than the national rate of 77.6%. The late ones land about an hour behind schedule. That rests on 3,658 flights, of which United Airlines flew 1,168 at 78.2% on time.

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

On time

74.3%

Arrivals under 15 minutes late, of 3,625 completed flights

Avg delay

58 min

Across delayed arrivals only, not all flights

Cancelled

0.68%

National rate is 1.81%

Best carrier

United

78.2% on time across 1,168 flights

These figures cover 3,658 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

Which airline is most reliable on DEN to BNA

The two carriers here are closely matched: 6 points separate the best from the worst. At that spread, schedule and price are better tie-breakers than reliability. Sample sizes are shown so you can see which rows are worth weighing.

On-time performance by carrier on DEN to BNA
Airline	Flights	On time	Avg delay	Cancelled	Grade
United Airlines	1,168	78.2%	59 min	0.43%	B+
Southwest Airlines	2,142	72.6%	56 min	0.79%	C+
Frontier Airlinesthin sample	348	72.4%	64 min	0.86%	C+

No carrier stands out. United tops the table at 78.2%, 6 points clear of the bottom, which is inside the range this kind of sample moves year to year.

Departure window

The best time of day to leave

Departure time matters more here than the choice of carrier. The gap between the best and worst window is 45 points, against 6 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am587 flights94.5%
8am–11am964 flights85.3%
11am–2pm506 flights71.8%
2pm–5pm584 flights64.1%
5pm–8pm792 flights62.4%
8pm–5am225 flights49.5%

Scale runs 40% to 100%. Rows with fewer than 30 flights show a dash.

The 8pm–5am window is where this operation falls apart: 49.5% 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 8am–11am window is the busiest, with 964 flights scheduled in it.

Across the year

When delays peak on this route

This route's year swings by 27 points from best month to worst, which is wide. An annual average tells you very little about the week you are actually flying, so read the strip rather than the headline if your dates are fixed.

Darker means more delays. Figures are on-time percentages.February best, July worst

July is the worst month at 59.3% on time, 27 points below February, the best at 86.5%. 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 370 flights.

Across the week, Saturday is the strongest day at 79.2% on time and Thursday the weakest at 70.5%. 9 points is a smaller lever than departure hour, but it is free.

Delay causes

Why this route gets delayed

One category carries most of the weight here. Late-arriving aircraft accounts for 51% of the 54,000 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
51%
Carrier
27%
National Airspace System
20%
Extreme weather
2%
Security
0%

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 54,000 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 53,540 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 are rare at 0.68%, 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 actually costs

7.9% 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 are the about an hour kind, 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 74.9% on time across 3,665 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 3,658 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 this route

Put together: the calendar is the biggest lever here, not the carrier or the hour. February runs 86.5% on time and July 59.3%, a swing of 27 points. If the dates move at all, move them out of July before you think about anything else. 3,625 completed flights over 12 months sit behind that.

Common questions

DEN to BNA questions

How often is DEN to BNA delayed?

About one flight in four arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 25.7% of the 3,658 flights in this analysis, against 22.4% nationally. Delayed flights are late by about an hour on average.

Which airline is most reliable on DEN to BNA?

United Airlines leads at 78.2% on time across 1,168 flights. Southwest Airlines is at the other end on 72.6%, a gap of 6 points. Sample size matters as much as the percentage: a rate built from a few hundred flights moves around far more than one built from ten thousand.

What time of day has the fewest delays on DEN to BNA?

The 5am–8am departure window is the strongest at 94.5% on time. The 8pm–5am window is the weakest at 49.5%, 45 points behind. Later departures inherit delays from earlier flights the same aircraft has already flown, which is why the curve slopes the way it does.

How bad are July delays on DEN to BNA?

July is the weakest month at 59.3% on time, compared with 86.5% in February. Across the year that is 27 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.

Where to go next

Direction matters. DEN to BNA and BNA to DEN are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.

Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Updated monthly. How this data is collected.

Key figures