Carrier route record
DLSEA→MCI
Delta Air Lines · Seattle to Kansas City
- Flights
- 364
- Period
- September 2025 to August 2026
- Share of route
- 32%
- Carriers
- 3
Historical statistics for September 2025 to August 2026, not live status. For today’s flights, check with Delta Air Lines.
Delta on SEA to MCI lands a B, level with the national rate of 77.3%. Roughly one flight in four arrives 15 minutes late or worse, and those flights are late by a little over an hour on average. That rests on 364 flights, with a median arrival 8 minutes early.
The US average over the same twelve months is 77.3%, so there is little to separate Delta on SEA to MCI from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
77.4%
Arrivals under 15 minutes late, of 354 completed flights
Avg delay
77 min
Across delayed arrivals only, not all flights
Cancelled
1.65%
National rate is 1.89%
Whole route
81.2%
Every carrier on SEA to MCI, 1,126 flights
These figures cover 364 flights between September 2025 and August 2026. Beyond the headline rate, 9.3% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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Carrier by carrier
Delta against every carrier on SEA to MCI
Delta flew 364 of the 1,126 flights on SEA to MCI, about 32% of it. Its 77.4% on time is 4 points worse than the route as a whole, which runs 81.2%. Ranked by on-time rate it is number two of three carriers on the route, where the range runs from Alaska at 84.3% to Southwest at 29.4%. One of those carriers flew fewer than 365 flights here, so treat their positions as rough.
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.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Alaska Airlines | 745 | 84.3% | 45 min | 0.40% | B+ |
| Delta Air Lines (this page)thin sample | 364 | 77.4% | 77 min | 1.65% | B |
| Southwest Airlinesthin sample | 17 | 29.4% | 76 min | 0.00% | F+ |
Flight by flight
Delta flight numbers on SEA to MCI
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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.
There are not enough flights in each departure window to split Delta's SEA to MCI record by time of day without the percentages moving on noise. The headline rate of 77.4% is the reliable figure here.
Across the year
Delta on SEA to MCI through the year
- Jul–Sep 202530 flights60.0%
- Oct–Dec 202591 flights76.4%
- Jan–Mar 202690 flights83.5%
- Apr–Jun 202691 flights80.9%
- Jul–Sep 202662 flights73.8%
Scale runs 50% to 90%.
Monthly volumes are too low here to break the year into twelve reliable readings. What the twelve-month total says is 77.4% on time across 364 flights.
Delta on SEA to MCI did not run the same all year. Its best quarter was Jan–Mar 2026 at 83.5% on time and its weakest Jul–Sep 2025 at 60.0%, a swing of 24 points on roughly 73 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 84.3% on time and Friday the weakest at 72.0%, a spread of 12 points.
Arrival by arrival
How late Delta on SEA to MCI runs when it is late
Delta on SEA to MCI often beats the schedule: 132 of 354 completed flights, 37%, arrived 15 minutes or more early. The 80 late arrivals split 26 under half an hour, 21 between 30 and 60 minutes, and 33 an hour or more.
- 15+ min early132 flights37.3%
- Within 15 min142 flights40.1%
- 15–29 min late26 flights7.3%
- 30–59 min late21 flights5.9%
- 1–2 hours late22 flights6.2%
- 2+ hours late11 flights3.1%
Scale runs 0% to 100%.
Share of 354 completed flights by arrival against schedule.
20 of 88 late departures made up the time and arrived on time, 23% of them. 12 flights left on time and still arrived late.
The worst days
Worst days for Delta on SEA to MCI
The latest arrival of the period was on 11 December 2025, 13 hours 39 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). The same cause led on four of the five worst days.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 11 December 2025 | 13 hours 39 minutes | Carrier |
| 6 January 2026 | 4 hours 24 minutes | Late-arriving aircraft |
| 12 July 2026 | 4 hours 13 minutes | Carrier |
| 21 July 2026 | 4 hours 5 minutes | Carrier |
| 24 August 2026 | 3 hours 42 minutes | Carrier |
Delay causes
Why Delta runs late on this route
Carrier accounts for 65% of the 6,179 delay minutes carriers reported here, and the remaining four split what is left.
- 65%Carrier
- 25%Late-arriving aircraft
- 9%National Airspace System
- 2%Extreme weather
The largest share of delay minutes, 65%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 3,992 of the 6,179 delay minutes reported here. The split is drawn from 6,179 reported delay minutes.
Cancellations sit at 1.65% against a national 1.89%, which is ordinary. Diversions add another 1.10%.
Connections and stage length
What a delay here costs
9.3% of arrivals land a full hour or more behind schedule, against 8.3% nationally. Ninety minutes is the honest minimum for a connection here, and two hours if the onward flight is on a separate ticket.
The 1,490 miles between these two airports put this in the middle of the US network, around two and a half to three hours of block time. That is enough cruise to absorb a ten-minute late pushback and not enough to absorb thirty.
The return leg is a different operation and performs like one: it runs 87.0% on time across 364 flights, 10 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 10 points of difference.
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 SEA to MCI
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 77.4% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 354 completed flights over 12 months sit behind that.
Related
Where to go next
- SEA to MCI, every carrier
- Delta on MCI to SEA, the return leg
- Alaska Airlines on SEA to MCI84.3%
- Delta Air Lines network-wide record
- Seattle-Tacoma International (SEA) delay statistics
- Kansas City International (MCI) delay statistics
- How often a connection fails at the major US hubs
- Connecting flights: how much buffer the data says you need
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.