MCI to SEA flight delays
Kansas City, MO (MCI) Seattle, WA (SEA) · 1,490 miles
1,131 flights · January 2025 – August 2026 · US Bureau of Transportation Statistics
83.38%
Arrived on time
Within 15 minutes of schedule
1.06%
Cancelled
Share of scheduled flights
71 min
When late, late by
Average across delayed arrivals
13 min
Delay per flight
Averaged over every flight flown
What the record says about this route
The shape of the lateness matters here. Flights on this route are not late often, but when they are late they are late by about 71 minutes — long enough to lose a connection or an evening. The on-time percentage looks reassuring and understates the consequence of being on the wrong flight.
The season swings this route hard. In February it ran 24.6 points more punctual than in December — a difference bigger than the one between the best and worst airlines on most routes. If the date is flexible, it is worth more than the carrier.
The route has been getting better. The later months in the record run 10.1 points more punctual than the earlier ones, which usually means a schedule that was too tight has been given more room.
The two directions do not behave alike. SEA to MCI arrives on time 5.6 points less often than the outbound. Delay accumulates through the flying day, so whichever direction is scheduled later tends to carry the worse record — which is an argument for booking the morning departure if the choice exists.
Which airline should you fly on this route?
Over January 2025 – August 2026, Delta Air Lines arrived on time most often on MCI to SEA. Alaska Airlines was late most often. Flights ran closest to schedule in February and worst in December.
Every airline on MCI to SEA
Ranked by how many flights each one operated. A carrier with fewer than 100 flights in the period is listed but not graded.
| Airline | Flights | On time | Cancelled | Avg delay | Grade |
|---|---|---|---|---|---|
| Alaska Airlines | 745 | 83.04% | 0.81% | 66 min | B |
| Delta Air Lines | 364 | 85.31% | 1.65% | 84 min | B |
| Southwest Airlines | 22 | 63.64% | 0% | 66 min | — |
Month by month
Share of flights that arrived within 15 minutes of schedule, by month flown.
The return leg
SEA to MCI Seattle back to Kansas City 77.74% on time COther routes from Kansas City
Common questions
Are flights from Kansas City to Seattle usually delayed?
83.38% of flights on the MCI to SEA route arrived within 15 minutes of schedule, so roughly 2 in every ten arrived late. That is better than the average route in this record.
Which airline is most on time from Kansas City to Seattle?
Delta Air Lines, at 85.31% on time across 364 flights. The least punctual on the route was Alaska Airlines at 83.04%.
How often are MCI to SEA flights cancelled?
1.06% of scheduled flights did not operate — about 11 in every thousand. That is in the normal range.
What is the best month to fly Kansas City to Seattle?
February, when 90.9% of flights arrived on time. The worst was December at 66.3%.
When MCI to SEA flights are late, how late are they?
About 71 minutes on average across the flights that arrived more than 15 minutes behind schedule.
What these figures do and do not tell you
Everything on this page is counted from the flights that actually operated on MCI to SEA during January 2025 – August 2026, as reported by the airlines to the US Bureau of Transportation Statistics. "On time" is the federal definition: arriving at the gate within 15 minutes of the scheduled time.
A route's record is a description of the past, not a forecast. Weather, air traffic control and the aircraft's earlier flights that day drive most delays, and none of them are predictable from a historical rate. What the record does tell you is whether this route runs late more often than others, and which carrier on it has the better history — which is the part you can actually act on when you book.
Cancellations are counted separately from delays because they are a different problem for a traveller: a late flight still gets you there. How the grade is calculated →