Carrier route record

DLSEA→BNA

Delta Air Lines · Seattle to Nashville

Flights: 511
Period: July 2025 to June 2026
Share of route: 35%
Carriers: 3

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

Delta on SEA to BNA earns a B+. More than four flights in five arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 7 points better than the national rate of 77.6%. When something does go wrong the average delay runs about an hour. That rests on 511 flights, with a median arrival 10 minutes early.

Set against the rest of the country, Delta's SEA to BNA record is 7 points better than the US average of 77.6%. That gap is worth roughly 70 fewer late arrivals for every thousand flights.

On time

84.6%

Arrivals under 15 minutes late, of 508 completed flights

Avg delay

61 min

Across delayed arrivals only, not all flights

Cancelled

0.59%

National rate is 1.81%

Whole route

78.6%

Every carrier on SEA to BNA, 1,479 flights

These figures cover 511 flights between July 2025 and June 2026. The median arrival is 10 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

Delta against every carrier on SEA to BNA

Delta flew 511 of the 1,479 flights on SEA to BNA, about 35% of it. Its 84.6% on time is 6 points better than the route as a whole, which runs 78.6%. Ranked by on-time rate it is first of three carriers on the route, where the range runs from Delta at 84.6% to Southwest at 64.8%. 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 SEA to BNA
Airline	Flights	On time	Avg delay	Cancelled	Grade
Delta Air Lines (this page)	511	84.6%	61 min	0.59%	B+
Alaska Airlines	843	77.0%	43 min	1.07%	B
Southwest Airlinesthin sample	125	64.8%	39 min	0.00%	D+

Flight by flight

Delta flight numbers on SEA to BNA

DL 81517:3583.4% · 290 flights

Departure window

When Delta 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 511 flights.

5am–8am—
8am–11am159 flights84.3%
11am–2pm—
2pm–5pm14 flights—
5pm–8pm336 flights84.1%
8pm–5am2 flights—

Scale runs 75% to 90%. Rows with fewer than 30 flights show a dash.

The 8am–11am window is the strongest at 84.3% on time. The full set of windows spans half a point.

Across the year

Delta on SEA to BNA through the year

Darker means more delays. Figures are on-time percentages.April best, October worst

April is the best month on the calendar at 96.6% 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 61 flights.

Across the week, Wednesday is the strongest day at 88.9% on time and Friday the weakest at 79.2%. 10 points is a smaller lever than departure hour, but it is free.

Delay causes

Why Delta runs late on this route

One category carries most of the weight here. Carrier accounts for 56% of the 4,779 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.

Carrier
56%
Late-arriving aircraft
28%
National Airspace System
15%
Extreme weather
2%

The largest share of delay minutes, 56%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. Unlike weather, that is a management outcome, and it is the category where the gap between two carriers on the same schedule is genuinely earned. It accounts for 2,671 of the 4,779 delay minutes reported here. The split is drawn from 4,779 reported delay minutes.

Cancellations are rare at 0.59%, 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

5.7% 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 about an hour, which a normal layover absorbs.

At 1,978 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 runs 83.4% on time across 511 flights, within about a point of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.

One caution: this is a thin sample. 511 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 Delta on SEA to BNA

Put together: treat all of this as provisional. 511 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 84.6% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 508 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