Route reliability record
DFW→SEA
Dallas-Fort Worth to Seattle
- Flights
- 5,227
- Period
- September 2025 to August 2026
- Distance
- 1,660 mi
- Carriers
- 4
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, 6 points worse than the national rate of 77.3%. The late ones land about an hour behind schedule. That rests on 5,227 DFW to SEA flights, of which Delta Air Lines flew 720 at 79.3% on time.
Best time to fly DFW to SEA: a 5am–8am departure, ideally on a Tuesday. Flights in that window arrived on time 82.8% of the time and Tuesday flights 73.9%, against 71.1% for the route overall.
Delta Air Lines is the most reliable of the three carriers covered here at 79.3% on time across 720 flights.
Key figures
On time
71.1%
Arrivals under 15 minutes late, of 5,127 completed flights
Avg delay
62 min
Across delayed arrivals only, not all flights
Cancelled
1.78%
National rate is 1.89%
Best carrier
Delta
79.3% on time across 720 flights
These figures cover 5,227 flights between September 2025 and August 2026. Beyond the headline rate, 8.2% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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Carrier by carrier
Which airline is most reliable on DFW to SEA
The choice of carrier is not cosmetic here. Delta Air Lines arrives on time 79.3% of the time; American Airlines manages 65.0%. Sample sizes sit next to every figure, because a two-point gap across 2,735 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Delta Air Lines | 720 | 79.3% | 89 min | 1.67% | B |
| Alaska Airlines | 1,758 | 77.2% | 53 min | 1.19% | B |
| American Airlines | 2,735 | 65.0% | 62 min | 2.19% | C |
| Frontier Airlinesthin sample | 14 | 57.1% | 28 min | 0.00% | D+ |
The spread between Delta and American is 14 points, wide enough that it should decide the booking. On a hundred trips that is 14 more arrivals inside the on-time window.
Flight by flight
Flights on DFW 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 Dallas-Fort Worth 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. DFW → SEADallas-Fort Worth to Seattle | Delta Air Lines | 78.0% | 79.3% | 1.67% | 5am–8am, Thu | DL 804 06:30 |
| 2. DFW → SEADallas-Fort Worth to Seattle | Alaska Airlines | 76.3% | 77.2% | 1.19% | 11am–2pm, Wed | AS 415 13:02 |
| 3. DFW → SEADallas-Fort Worth to Seattle | American Airlines | 63.6% | 65.0% | 2.19% | 5am–8am, Tue | AA 707 07:10 |
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 29 points, against 14 points between the best and worst carrier.
- 5am–8am905 flights82.8%
- 8am–11am1,109 flights76.5%
- 11am–2pm589 flights75.6%
- 2pm–5pm985 flights70.1%
- 5pm–8pm891 flights65.2%
- 8pm–5am748 flights53.8%
Scale runs 45% to 90%.
The 8pm–5am window is where this operation falls apart: 53.8% on time, against 82.8% 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 8am–11am window is the busiest, with 1,109 flights scheduled in it.
Explore
Filter DFW 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 DFW to SEA, the best departure window is 5am–8am at 82.8% on time and the worst is 8pm–5am at 53.8%, a wide gap of 29.0 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am82.8%
- 8–11am76.5%
- 11am–2pm75.6%
- 2–5pm70.1%
- 5–8pm65.2%
- 8pm–5am53.8%
best all US flightsScale 45% to 95%.
Across the year
When delays peak on this route
This route's year swings by 17 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 60.8% on time, against 77.7% 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 502 flights.
Across the week, Tuesday is the strongest day at 73.9% on time and Sunday the weakest at 66.0%, a spread of 8 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 92,000 reported delay minutes.
- 40%Late-arriving aircraft
- 34%Carrier
- 17%National Airspace System
- 8%Extreme weather
- 0%Security
40% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 92,000 reported delay minutes here, that single category outweighs weather by 5 to one. The split is drawn from 91,544 reported delay minutes.
The largest share of delay minutes, 34%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 32,000 of the 92,000 delay minutes reported here.
Cancellations sit at 1.78% against a national 1.89%, which is ordinary. Diversions add another 0.13%.
Connections and stage length
What a delay here actually costs
8.2% 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 an hour, which a normal layover absorbs.
At 1,660 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 78.0% on time across 5,228 flights, 7 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 7 points of difference.
The sample behind these figures is 5,227 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 77.7% on time and December 60.8%, a swing of 17 points. If the dates move at all, move them out of December before you think about anything else. 5,127 completed flights over 12 months sit behind that.
Common questions
DFW to SEA questions
How often is DFW to SEA delayed?
Roughly one flight in three arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 28.9% of the 5,227 flights in this analysis, against 22.7% nationally. Delayed flights are late by about an hour on average.
Which airline is most reliable on DFW to SEA?
Delta Air Lines leads at 79.3% on time across 720 flights. American Airlines is at the other end on 65.0%, a gap of 14 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 DFW to SEA?
The 5am–8am departure window is the strongest at 82.8% on time. The 8pm–5am window is the weakest at 53.8%, 29 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 DFW to SEA?
December is the weakest month at 60.8% on time, compared with 77.7% in February. Across the year that is 17 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 DFW — the return legseparate record
- Dallas/Fort Worth International (DFW) delay statistics
- Seattle-Tacoma International (SEA) delay statistics
- Delta Air Lines on DFW to SEA79.3%
- Alaska Airlines on DFW to SEA77.2%
- American Airlines on DFW to SEA65.0%
- DFW to ORD, a related route68.8%
- LAX to SEA, a related route85.0%
- DFW to ATL, a related route75.6%
- Delta Air Lines on-time record79.3%
- Alaska Airlines on-time record77.2%
- American Airlines on-time record65.0%
- Same route, different airline: where the carrier you pick matters most
- Why the first flight of the morning is statistically safest
Direction matters. DFW to SEA and SEA to DFW 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.