Route reliability record
BNA→SEA
Nashville to Seattle
- Flights
- 1,479
- Period
- July 2025 to June 2026
- Distance
- 1,978 mi
- Carriers
- 3
This route 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 55 minutes behind schedule. That rests on 1,479 BNA to SEA flights, of which Delta Air Lines flew 511 at 83.4% on time.
Best time to fly BNA to SEA: a 8am–11am departure, ideally on a Wednesday. Flights in that window arrived on time 85.3% of the time and Wednesday flights 81.1%, against 72.7% for the route overall.
The national on-time rate over the same period is 77.6%, so this route runs 5 points behind the country as a whole. Across a thousand flights that is about 49 extra late arrivals.
Key figures
On time
72.7%
Arrivals under 15 minutes late, of 1,459 completed flights
Avg delay
53 min
Across delayed arrivals only, not all flights
Cancelled
1.15%
National rate is 1.81%
Best carrier
Delta
83.4% on time across 511 flights
These figures cover 1,479 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
Which airline is most reliable on BNA to SEA
The choice of carrier is not cosmetic here. Delta Air Lines arrives on time 83.4% of the time; Alaska Airlines manages 70.3%. Sample sizes sit next to every figure, because a two-point gap across 843 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Delta Air Lines | 511 | 83.4% | 66 min | 0.78% | B+ |
| Alaska Airlines | 843 | 70.3% | 49 min | 1.42% | C |
| Southwest Airlinesthin sample | 125 | 44.7% | 52 min | 0.80% | F+ |
The spread between Delta and Alaska is 13 points, wide enough that it should decide the booking. On a hundred trips that is 13 more arrivals inside the on-time window.
Flight by flight
Flights on BNA to SEA
The flight numbers below flew this route at least 250 times in the period, busiest first. Each has its own record, with its schedule and delay causes.
Best ways to make this trip
The most reliable ways to fly Nashville to Seattle
Every airline on this route, ranked by how often a scheduled flight actually operated and arrived on time, with its best departure time and most punctual flight number. No nearby airport pair beat these.
| Option | Airline | Success | On time | Cancelled | Best departure | Most punctual flight |
|---|---|---|---|---|---|---|
| 1. BNA → SEANashville to Seattle | Delta Air Lines | 82.7% | 83.4% | 0.78% | 5am–8am, Wed | DL 372 07:00 |
| 2. BNA → SEANashville to Seattle | Alaska Airlines | 69.3% | 70.3% | 1.42% | 8am–11am, Wed | — |
Success is the share of scheduled flights that operated and arrived less than 15 minutes late, so a cancelled flight counts against it. “(route)” means the best time comes from every carrier on the route rather than this airline alone.
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 25 points, against 13 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am703 flights79.4%
- 8am–11am172 flights85.3%
- 11am–2pm8 flights—
- 2pm–5pm181 flights65.7%
- 5pm–8pm405 flights60.0%
- 8pm–5am10 flights—
Scale runs 50% to 90%. Rows with fewer than 30 flights show a dash.
The 5pm–8pm window is where this operation falls apart: 60.0% on time, against 85.3% for the 8am–11am 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 703 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 29 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.
December is the weak month at 55.1% on time, against 84.2% in February. Winter delays cluster: a single storm system can account for most of a month's shortfall, so an average December hides both very good weeks and genuinely unflyable days. July was the busiest month here, with 188 flights.
Across the week, Wednesday is the strongest day at 81.1% on time and Friday the weakest at 67.3%. 14 points is a smaller lever than departure hour, but it is free.
Delay causes
Why this route gets delayed
Carriers report a reason for every delay minute they cause, in five DOT categories. The split below is by minutes, not by number of flights, so a handful of very long weather delays weighs as much as many short ones. It covers 21,000 reported delay minutes.
- 37%Carrier
- 32%Late-arriving aircraft
- 27%National Airspace System
- 4%Extreme weather
- 0%Security
The largest share of delay minutes, 37%, 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 7,725 of the 21,000 delay minutes reported here. The split is drawn from 21,094 reported delay minutes.
The practical consequence: the 8am–11am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 85.3% on time here.
Cancellations sit at 1.15% against a national 1.81%, which is ordinary. Diversions add another 0.20%.
Connections and stage length
What a delay here actually costs
6.4% 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 55 minutes, 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 is a different operation and performs like one: it runs 78.6% on time across 1,479 flights, 6 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 6 points of difference.
The sample behind these figures is 1,479 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.
Work out the risk of missing a connection in SEA after this flight
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 84.2% on time and December 55.1%, a swing of 29 points. If the dates move at all, move them out of December before you think about anything else. 1,459 completed flights over 12 months sit behind that.
Common questions
BNA to SEA questions
How often is BNA to SEA delayed?
Roughly one flight in four arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 27.3% of the 1,479 flights in this analysis, against 22.4% nationally. Delayed flights are late by roughly 55 minutes on average.
Which airline is most reliable on BNA to SEA?
Delta Air Lines leads at 83.4% on time across 511 flights. Alaska Airlines is at the other end on 70.3%, a gap of 13 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 BNA to SEA?
The 8am–11am departure window is the strongest at 85.3% on time. The 5pm–8pm window is the weakest at 60.0%, 25 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 December delays on BNA to SEA?
December is the weakest month at 55.1% on time, compared with 84.2% in February. Across the year that is 29 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.
Related
Where to go next
- SEA to BNA — the return legseparate record
- Nashville International (BNA) delay statistics
- Seattle-Tacoma International (SEA) delay statistics
- Delta Air Lines on BNA to SEA83.4%
- Alaska Airlines on BNA to SEA70.3%
- Southwest Airlines on BNA to SEA44.7%
- BNA to ORD, a related route70.4%
- LAX to SEA, a related route85.4%
- BNA to DCA, a related route73.3%
- Delta Air Lines on-time record83.4%
- Alaska Airlines on-time record70.3%
- Southwest Airlines on-time record44.7%
- Same route, different airline: where the carrier you pick matters most
- Why the first flight of the morning is statistically safest
Direction matters. BNA to SEA and SEA to BNA are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
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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.