Route reliability record
BNA→SEA
Nashville to Seattle
- Flights
- 1,481
- Period
- September 2025 to August 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 77.3%. The late ones land about 50 minutes behind schedule. That rests on 1,481 BNA to SEA flights, of which Delta Air Lines flew 516 at 79.8% on time.
Best time to fly BNA to SEA: a 8am–11am departure, ideally on a Wednesday. Flights in that window arrived on time 89.1% of the time and Wednesday flights 77.7%, against 72.4% for the route overall.
The national on-time rate over the same period is 77.3%, 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
72.4%
Arrivals under 15 minutes late, of 1,462 completed flights
Avg delay
49 min
Across delayed arrivals only, not all flights
Cancelled
1.15%
National rate is 1.89%
Best carrier
Delta
79.8% on time across 516 flights
These figures cover 1,481 flights between September 2025 and August 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.
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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 79.8% of the time; Alaska Airlines manages 72.7%. Sample sizes sit next to every figure, because a two-point gap across 845 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Delta Air Lines | 516 | 79.8% | 60 min | 1.16% | B |
| Alaska Airlines | 845 | 72.7% | 44 min | 1.18% | C |
| Southwest Airlinesthin sample | 120 | 38.7% | 50 min | 0.83% | F+ |
Delta leads Alaska by 7 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.
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.
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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 | 78.9% | 79.8% | 1.16% | 5am–8am, Wed | DL 372 07:00 |
| 2. BNA → SEANashville to Seattle | Alaska Airlines | 71.8% | 72.7% | 1.18% | 8am–11am, Mon | — |
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 69 points, against 7 points between the best and worst carrier.
- 5am–8am710 flights79.1%
- 8am–11am166 flights89.1%
- 11am–2pm34 flights20.6%
- 2pm–5pm177 flights68.4%
- 5pm–8pm394 flights59.6%
- 8pm–5am—
Scale runs 10% to 95%. Rows with fewer than 30 flights show a dash.
The weak window here is the middle of the day, not the evening: 11am–2pm runs 20.6% on time against 89.1% for 8am–11am. That shape usually means a departure bank rather than an accumulating delay, so the recovery later in the afternoon is real rather than noise. The 5am–8am window is the busiest, with 710 flights scheduled in it.
Explore
Filter BNA to SEA by airline, time, month and day
Pick a breakdown and a carrier. The dashed mark on each row is the same slice for every US flight.
On BNA to SEA, the best departure window is 8am–11am at 89.1% on time and the worst is 11am–2pm at 20.6%, a wide gap of 68.5 points. All US flights leaving 8am–11am ran 83.9%.
- 5–8am79.1%
- 8–11am89.1%
- 11am–2pm20.6%
- 2–5pm68.4%
- 5–8pm59.6%
- 8pm–5am—
best all US flightsScale 10% to 95%. Cells under 30 flights show a dash.
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 185 flights.
Across the week, Wednesday is the strongest day at 77.7% on time and Thursday the weakest at 66.5%, a spread of 11 points.
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 20,000 reported delay minutes.
- 40%Carrier
- 30%National Airspace System
- 25%Late-arriving aircraft
- 5%Extreme weather
- 0%Security
The largest share of delay minutes, 40%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 7,875 of the 20,000 delay minutes reported here. The split is drawn from 19,796 reported delay minutes.
Cancellations sit at 1.15% against a national 1.89%, which is ordinary. Diversions add another 0.14%.
Connections and stage length
What a delay here actually costs
5.7% of arrivals land an hour or more late, close to the national 8.3%, so a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last about 50 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 80.6% on time across 1,481 flights, 8 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 8 points of difference.
The sample behind these figures is 1,481 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. 1,462 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 27.6% of the 1,481 flights in this analysis, against 22.7% nationally. Delayed flights are late by about 50 minutes on average.
Which airline is most reliable on BNA to SEA?
Delta Air Lines leads at 79.8% on time across 516 flights. Alaska Airlines is at the other end on 72.7%, a gap of 7 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 89.1% on time. The 11am–2pm window is the weakest at 20.6%, 69 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 SEA79.8%
- Alaska Airlines on BNA to SEA72.7%
- Southwest Airlines on BNA to SEA38.7%
- BNA to ORD, a related route70.9%
- LAX to SEA, a related route85.0%
- BNA to DCA, a related route71.3%
- Delta Air Lines on-time record79.8%
- Alaska Airlines on-time record72.7%
- Southwest Airlines on-time record38.7%
- The best time of day to fly, according to 7.05 million flight records
- Worst months to fly in the US, ranked by the data
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, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.