Carrier route record

DLDFW→SEA

Delta Air Lines · Dallas-Fort Worth to Seattle

Flights: 712
Period: July 2025 to June 2026
Share of route: 14%
Carriers: 4

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

Delta on DFW to SEA lands a B, about a point better than the national rate of 77.6%. About one flight in five arrives 15 minutes late or worse, and those flights are late by an hour and a half on average. That is a workable record, not a spotless one. That rests on 712 flights. The strongest carrier on the route with a full sample, Alaska Airlines, flew 1,756 at 72.7% on time.

The US average over the same twelve months is 77.6%, so there is little to separate Delta on DFW to SEA from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.

On time

78.9%

Arrivals under 15 minutes late, of 698 completed flights

Avg delay

88 min

Across delayed arrivals only, not all flights

Cancelled

1.69%

National rate is 1.81%

Whole route

69.5%

Every carrier on DFW to SEA, 5,232 flights

These figures cover 712 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

Delta against every carrier on DFW to SEA

Delta flew 712 of the 5,232 flights on DFW to SEA, about 14% of it. Its 78.9% on time is 9 points better than the route as a whole, which runs 69.5%. Ranked by on-time rate it is first of four carriers on the route, where the range runs from Delta at 78.9% to American at 65.0%. One of those carriers flew fewer than 365 flights here, so treat their positions as rough.

The choice of carrier is not cosmetic here. Alaska Airlines arrives on time 72.7% of the time; American Airlines manages 65.0%. Sample sizes sit next to every figure, because a two-point gap across 2,736 flights means less than a ten-point one.

On-time performance by carrier on DFW to SEA
Airline	Flights	On time	Avg delay	Cancelled	Grade
Delta Air Lines (this page)	712	78.9%	88 min	1.69%	B
Alaska Airlines	1,756	72.7%	57 min	1.48%	C
Frontier Airlinesthin sample	28	67.9%	43 min	0.00%	C+
American Airlines	2,736	65.0%	64 min	2.67%	C

Alaska leads American by 8 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.

Flight by flight

Delta flight numbers on DFW to SEA

DL 80407:1085.0% · 365 flights

Departure window

When Delta runs best on this route

Departure time matters more here than the choice of carrier. The gap between the best and worst window is 12 points, against 8 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am351 flights85.0%
8am–11am14 flights—
11am–2pm—
2pm–5pm347 flights72.7%
5pm–8pm—
8pm–5am—

Scale runs 65% to 90%. Rows with fewer than 30 flights show a dash.

Book the early departure. Flights leaving between 5am–8am arrive on time 85.0% of the time, against 72.7% for the afternoon window. That is 12 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 5am–8am window is the busiest, with 351 flights scheduled in it.

Across the year

Delta on DFW to SEA through the year

Darker means more delays. Figures are on-time percentages.July best, December worst

December is the weak month at 69.0% on time, against 89.7% in July. 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. March was the busiest month here, with 62 flights.

Across the week, Tuesday is the strongest day at 83.7% on time and Monday the weakest at 72.0%. 12 points is a smaller lever than departure hour, but it is free.

Delay causes

Why Delta runs late on this route

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 13,000 reported delay minutes.

Late-arriving aircraft
38%
Carrier
37%
National Airspace System
16%
Extreme weather
9%
Security
0%

38% 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 13,000 reported delay minutes here, that single category outweighs weather by 4 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 12,955 reported delay minutes.

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 4,796 of the 13,000 delay minutes reported here.

Cancellations sit at 1.69% against a national 1.81%, which is ordinary. Diversions add another 0.28%.

Connections and stage length

What a delay here costs

7.3% 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 an hour and a half, 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 75.1% on time across 712 flights, 4 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 4 points of difference.

One caution: this is a thin sample. 712 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 DFW to SEA

Put together: treat all of this as provisional. 712 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 78.9% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 698 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