Carrier route record

DLFLL→SEA

Delta Air Lines · Fort Lauderdale to Seattle

Flights: 364
Period: July 2025 to June 2026
Share of route: 44%
Carriers: 2

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

Delta on FLL to SEA sits in the middle of the pack with a C. Close to three flights in four arrive on time by the DOT's definition, 4 points worse than the national rate of 77.6%. The late ones land a little over an hour behind schedule. That rests on 364 flights, with a median arrival 5 minutes early.

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

On time

73.8%

Arrivals under 15 minutes late, of 355 completed flights

Avg delay

79 min

Across delayed arrivals only, not all flights

Cancelled

1.65%

National rate is 1.81%

Whole route

69.7%

Every carrier on FLL to SEA, 826 flights

These figures cover 364 flights between July 2025 and June 2026. The median arrival is 5 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 FLL to SEA

Delta flew 364 of the 826 flights on FLL to SEA, about 44% of it. Its 73.8% on time is 4 points better than the route as a whole, which runs 69.7%. Ranked by on-time rate it is first of two carriers on the route, where the range runs from Delta at 73.8% to Alaska at 66.5%.

Only one carrier clears this site's 365-flight floor here, so there is no comparison to draw. The table below is the full picture.

On-time performance by carrier on FLL to SEA
Airline	Flights	On time	Avg delay	Cancelled	Grade
Delta Air Lines (this page)thin sample	364	73.8%	79 min	1.65%	C
Alaska Airlines	462	66.5%	56 min	1.30%	C

Departure window

When Delta runs best on this route

Departure time is the single lever a traveller controls, and it moves the odds more than most people expect. Each bar below is the on-time rate for flights scheduled to leave inside that window, across 364 flights.

5am–8am—
8am–11am267 flights75.6%
11am–2pm—
2pm–5pm—
5pm–8pm97 flights68.8%
8pm–5am—

Scale runs 60% to 80%. Rows with fewer than 30 flights show a dash.

The early departures do better, though not dramatically: 75.6% on time for the 8am–11am window against 68.8% for 5pm–8pm. Worth taking if the schedule allows, not worth an extra connection. The 8am–11am window is the busiest, with 267 flights scheduled in it.

Across the year

Delta on FLL to SEA through the year

Jul–Sep 202592 flights67.0%
Oct–Dec 202591 flights71.9%
Jan–Mar 202690 flights65.5%
Apr–Jun 202691 flights90.1%

Scale runs 55% to 95%. Rows with fewer than 30 flights show a dash.

Monthly volumes are too low here to break the year into twelve reliable readings. What the twelve-month total says is 73.8% on time across 364 flights.

Delta on FLL to SEA did not run the same all year. Its best quarter was Apr–Jun 2026 at 90.1% on time and its weakest Jan–Mar 2026 at 65.5%, a swing of 25 points on roughly 91 flights a quarter. The twelve-month rate averages over that, so if you are flying in a weak quarter the quarter's own figure is the better guide.

Across the week, Saturday is the strongest day at 82.0% on time and Tuesday the weakest at 61.5%. 21 points is a smaller lever than departure hour, but it is free.

Delay causes

Why Delta runs late on this route

One category carries most of the weight here. Late-arriving aircraft accounts for 48% of the 7,298 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.

Late-arriving aircraft
48%
Carrier
32%
National Airspace System
17%
Extreme weather
3%

48% 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 7,298 reported delay minutes here, that single category outweighs weather by 19 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 7,298 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 75.6% on time here.

Cancellations sit at 1.65% against a national 1.81%, which is ordinary. Diversions add another 0.82%.

Connections and stage length

What a delay here costs

7.9% 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 last a little over an hour, which a normal layover absorbs.

At 2,717 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 runs 73.8% on time across 364 flights, within half a point of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.

One caution: this is a thin sample. 364 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 FLL to SEA

Put together: treat all of this as provisional. 364 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 73.8% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 355 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