Route reliability record
SEA→DFW
Seattle to Dallas-Fort Worth
- Flights
- 5,233
- Period
- July 2025 to June 2026
- Distance
- 1,660 mi
- Carriers
- 4
This route lands a B, level with the national rate of 77.6%. Roughly one flight in four arrive 15 minutes late or worse, and those flights are late by a little over an hour on average. That is a workable record, not a spotless one. That rests on 5,233 flights, of which Alaska Airlines flew 1,755 at 78.9% on time.
Alaska Airlines is the most reliable of the three carriers covered here at 78.9% on time across 1,755 flights.
Key figures
On time
77.6%
Arrivals under 15 minutes late, of 5,073 completed flights
Avg delay
79 min
Across delayed arrivals only, not all flights
Cancelled
2.04%
National rate is 1.81%
Best carrier
Alaska
78.9% on time across 1,755 flights
These figures cover 5,233 flights between July 2025 and June 2026. The median arrival is 7 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 SEA to DFW
The three carriers here are closely matched: 4 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.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Alaska Airlines | 1,755 | 78.9% | 44 min | 1.03% | B |
| American Airlines | 2,738 | 77.6% | 98 min | 2.81% | B |
| Delta Air Lines | 712 | 75.1% | 83 min | 1.69% | B |
| Frontier Airlinesthin sample | 28 | 46.4% | 84 min | 0.00% | F+ |
No carrier stands out. Alaska tops the table at 78.9%, 4 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 21 points, against 4 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am933 flights91.2%
- 8am–11am1,266 flights78.9%
- 11am–2pm748 flights70.1%
- 2pm–5pm526 flights70.6%
- 5pm–8pm979 flights73.5%
- 8pm–5am781 flights76.1%
Scale runs 60% 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 70.1% on time against 91.2% for 5am–8am. 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 8am–11am window is the busiest, with 1,266 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 23 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.
July is the worst month at 64.8% on time, 23 points below February, the best at 88.0%. 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 505 flights.
Across the week, Wednesday is the strongest day at 83.2% on time and Sunday the weakest at 71.3%. 12 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. Carrier accounts for 47% of the 89,000 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.
- 47%Carrier
- 36%Late-arriving aircraft
- 14%National Airspace System
- 2%Extreme weather
- 0%Security
36% 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 89,000 reported delay minutes here, that single category outweighs weather by 18 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 89,399 reported delay minutes.
The largest share of delay minutes, 47%, 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 42,000 of the 89,000 delay minutes reported here.
Cancellations sit at 2.04% against a national 1.81%, which is ordinary. Diversions add another 1.01%.
Connections and stage length
What a delay here actually costs
6.9% 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 a little over an hour kind, 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 69.5% on time across 5,232 flights, 8 points below 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 5,233 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 88.0% on time and July 64.8%, a swing of 23 points. If the dates move at all, move them out of July before you think about anything else. 5,073 completed flights over 12 months sit behind that.
Common questions
SEA to DFW questions
How often is SEA to DFW delayed?
Roughly 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 22.4% of the 5,233 flights in this analysis, against 22.4% nationally. Delayed flights are late by a little over an hour on average.
Which airline is most reliable on SEA to DFW?
Alaska Airlines leads at 78.9% on time across 1,755 flights. Delta Air Lines is at the other end on 75.1%, a gap of 4 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 SEA to DFW?
The 5am–8am departure window is the strongest at 91.2% on time. The 11am–2pm window is the weakest at 70.1%, 21 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 SEA to DFW?
July is the weakest month at 64.8% on time, compared with 88.0% in February. Across the year that is 23 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
- DFW to SEA — the return legseparate record
- Seattle-Tacoma International (SEA) delay statistics
- Dallas/Fort Worth International (DFW) delay statistics
- Alaska Airlines on-time record78.9%
- American Airlines on-time record77.6%
- Delta Air Lines on-time record75.1%
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.04 million flight records
Direction matters. SEA to DFW and DFW to SEA 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.