Route reliability record
SEA→MSP
Seattle to Minneapolis
- Flights
- 2,689
- Period
- July 2025 to June 2026
- Distance
- 1,399 mi
- Carriers
- 2
This route earns a A+. More than four flights in five arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 8 points better than the national rate of 77.6%. When something does go wrong the average delay runs about an hour. That rests on 2,689 flights, of which Delta Air Lines flew 1,736 at 88.5% on time.
Set against the rest of the country, this route's record is 8 points better than the US average of 77.6%. That gap is worth roughly 79 fewer late arrivals for every thousand flights.
Key figures
On time
85.5%
Arrivals under 15 minutes late, of 2,659 completed flights
Avg delay
55 min
Across delayed arrivals only, not all flights
Cancelled
0.89%
National rate is 1.81%
Best carrier
Delta
88.5% on time across 1,736 flights
These figures cover 2,689 flights between July 2025 and June 2026. The median arrival is 8 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 MSP
The choice of carrier is not cosmetic here. Delta Air Lines arrives on time 88.5% of the time; Alaska Airlines manages 80.0%. Sample sizes sit next to every figure, because a two-point gap across 953 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Delta Air Lines | 1,736 | 88.5% | 66 min | 0.81% | A+ |
| Alaska Airlines | 953 | 80.0% | 44 min | 1.05% | B |
Delta leads Alaska by 9 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.
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 16 points, against 9 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am366 flights95.3%
- 8am–11am806 flights85.9%
- 11am–2pm563 flights81.0%
- 2pm–5pm220 flights84.7%
- 5pm–8pm466 flights78.9%
- 8pm–5am268 flights92.1%
Scale runs 70% to 100%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 95.3% of the time, against 78.9% for the evening window. That is 16 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 8am–11am window is the busiest, with 806 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 17 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 75.4% on time, 17 points below May, the best at 92.4%. 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 295 flights.
Across the week, Wednesday is the strongest day at 89.5% on time and Sunday the weakest at 82.4%. 7 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 21,000 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
- 31%Late-arriving aircraft
- 18%National Airspace System
- 4%Extreme weather
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 10,000 of the 21,000 delay minutes reported here. The split is drawn from 21,248 reported delay minutes.
The practical consequence: the 5am–8am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 95.3% on time here.
Cancellations are rare at 0.89%, below the national 1.81% and low enough to earn the plus on the grade. Roughly one flight in 100 is called off; the risk here is arriving late, not not arriving.
Connections and stage length
What a delay here actually costs
Badly late arrivals are rare here: only 3.5% land an hour or more behind schedule, against 8.1% nationally. Connections built on this flight are about as safe as US domestic connections get, though a cancelled flight still ignores every layover you give it.
The 1,399 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. It is also long enough that the aircraft usually flies three or four legs a day rather than six, which slows how fast delay compounds.
The return leg is a different operation and performs like one: it runs 81.1% on time across 2,690 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.
The sample behind these figures is 2,689 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. May runs 92.4% on time and July 75.4%, a swing of 17 points. If the dates move at all, move them out of July before you think about anything else. 2,659 completed flights over 12 months sit behind that.
Common questions
SEA to MSP questions
How often is SEA to MSP delayed?
About one flight in seven arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 14.5% of the 2,689 flights in this analysis, against 22.4% nationally. Delayed flights are late by about an hour on average.
Which airline is most reliable on SEA to MSP?
Delta Air Lines leads at 88.5% on time across 1,736 flights. Alaska Airlines is at the other end on 80.0%, a gap of 9 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 MSP?
The 5am–8am departure window is the strongest at 95.3% on time. The 5pm–8pm window is the weakest at 78.9%, 16 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 MSP?
July is the weakest month at 75.4% on time, compared with 92.4% in May. Across the year that is 17 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
- MSP to SEA — the return legseparate record
- Seattle-Tacoma International (SEA) delay statistics
- Minneapolis-St Paul International (MSP) delay statistics
- Delta Air Lines on-time record88.5%
- Alaska Airlines on-time record80.0%
- The best time of day to fly, according to 7.04 million flight records
- Worst months to fly in the US, ranked by the data
Direction matters. SEA to MSP and MSP 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.