Route reliability record
MSP→SEA
Minneapolis to Seattle
- Flights
- 2,676
- Period
- September 2025 to August 2026
- Distance
- 1,399 mi
- Carriers
- 2
This route lands a B+, 4 points better than the national rate of 77.3%. About one flight in five arrives 15 minutes late or worse, and those flights are late by about an hour on average. That rests on 2,676 MSP to SEA flights, of which Alaska Airlines flew 931 at 81.4% on time.
Best time to fly MSP to SEA: a 8am–11am departure, ideally on a Saturday. Flights in that window arrived on time 87.4% of the time and Saturday flights 83.2%, against 80.9% for the route overall.
The US average over the same twelve months is 77.3%, so there is little to separate this route from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
80.9%
Arrivals under 15 minutes late, of 2,646 completed flights
Avg delay
62 min
Across delayed arrivals only, not all flights
Cancelled
0.97%
National rate is 1.89%
Best carrier
Alaska
81.4% on time across 931 flights
These figures cover 2,676 flights between September 2025 and August 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.
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Carrier by carrier
Which airline is most reliable on MSP to SEA
The two carriers here are closely matched: about a point separate the best from the worst. At that spread, schedule and price are better tie-breakers than reliability. Sample sizes are shown so you can see which rows are worth weighing.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Alaska Airlines | 931 | 81.4% | 69 min | 1.18% | B |
| Delta Air Lines | 1,745 | 80.6% | 59 min | 0.86% | B+ |
No carrier stands out. Alaska tops the table at 81.4%, about a point clear of the bottom, which is inside the range this kind of sample moves year to year.
Flight by flight
Flights on MSP to SEA
The flight numbers below flew this route at least 250 times in the period, busiest first. Each has its own record, with its schedule and delay causes.
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Best ways to make this trip
The most reliable ways to fly Minneapolis to Seattle
Every airline on this route, ranked by how often a scheduled flight actually operated and arrived on time, with its best departure time and most punctual flight number. No nearby airport pair beat these.
| Option | Airline | Success | On time | Cancelled | Best departure | Most punctual flight |
|---|---|---|---|---|---|---|
| 1. MSP → SEAMinneapolis to Seattle | Alaska Airlines | 80.4% | 81.4% | 1.18% | 5pm–8pm, Sun | AS 387 07:00 |
| 2. MSP → SEAMinneapolis to Seattle | Delta Air Lines | 79.9% | 80.6% | 0.86% | 5am–8am, Tue | DL 868 08:50 |
Success is the share of scheduled flights that operated and arrived less than 15 minutes late, so a cancelled flight counts against it. “(route)” means the best time comes from every carrier on the route rather than this airline alone.
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 14 points, against about a point between the best and worst carrier.
- 5am–8am463 flights87.1%
- 8am–11am530 flights87.4%
- 11am–2pm233 flights82.4%
- 2pm–5pm608 flights73.0%
- 5pm–8pm528 flights77.5%
- 8pm–5am314 flights80.4%
Scale runs 65% to 95%.
Book the morning departure. Flights leaving between 8am–11am arrive on time 87.4% of the time, against 73.0% for the afternoon window. That is 14 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 2pm–5pm window is the busiest, with 608 flights scheduled in it.
Explore
Filter MSP to SEA by airline, time, month and day
Pick a breakdown and a carrier. The dashed mark on each row is the same slice for every US flight.
On MSP to SEA, the best departure window is 8am–11am at 87.4% on time and the worst is 2pm–5pm at 73.0%, a wide gap of 14.4 points. All US flights leaving 8am–11am ran 83.9%.
- 5–8am87.1%
- 8–11am87.4%
- 11am–2pm82.4%
- 2–5pm73.0%
- 5–8pm77.5%
- 8pm–5am80.4%
best all US flightsScale 60% to 95%.
Across the year
When delays peak on this route
This route's year swings by 41 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.
December is the weak month at 52.2% on time, against 93.3% in April. 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. July was the busiest month here, with 290 flights.
Across the week, Saturday is the strongest day at 83.2% on time and Sunday the weakest at 78.7%, a spread of 5 points.
Delay causes
Why this route gets delayed
Carrier accounts for 47% of the 31,000 delay minutes carriers reported here, and the remaining four split what is left.
- 47%Carrier
- 25%National Airspace System
- 24%Late-arriving aircraft
- 4%Extreme weather
- 0%Security
The largest share of delay minutes, 47%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 15,000 of the 31,000 delay minutes reported here. The split is drawn from 31,386 reported delay minutes.
Cancellations sit at 0.97% against a national 1.89%, which is ordinary. Diversions add another 0.15%.
Connections and stage length
What a delay here actually costs
5.3% of arrivals land an hour or more late, close to the national 8.3%, so a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last about an hour, which a normal layover absorbs.
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.
The return leg is a different operation and performs like one: it runs 87.2% on time across 2,676 flights, 6 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 6 points of difference.
The sample behind these figures is 2,676 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.
Work out the risk of missing a connection in SEA after this flight
What to do with this
Booking this route
Put together: the calendar is the biggest lever here, not the carrier or the hour. April runs 93.3% on time and December 52.2%, a swing of 41 points. If the dates move at all, move them out of December before you think about anything else. 2,646 completed flights over 12 months sit behind that.
Common questions
MSP to SEA questions
How often is MSP to SEA delayed?
About one flight in five arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 19.1% of the 2,676 flights in this analysis, against 22.7% nationally. Delayed flights are late by about an hour on average.
Which airline is most reliable on MSP to SEA?
Alaska Airlines leads at 81.4% on time across 931 flights. Delta Air Lines is at the other end on 80.6%, a gap of about a point. 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 MSP to SEA?
The 8am–11am departure window is the strongest at 87.4% on time. The 2pm–5pm window is the weakest at 73.0%, 14 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 December delays on MSP to SEA?
December is the weakest month at 52.2% on time, compared with 93.3% in April. Across the year that is 41 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
- SEA to MSP — the return legseparate record
- Minneapolis-St Paul International (MSP) delay statistics
- Seattle-Tacoma International (SEA) delay statistics
- Alaska Airlines on MSP to SEA81.4%
- Delta Air Lines on MSP to SEA80.6%
- MSP to ORD, a related route70.0%
- LAX to SEA, a related route85.0%
- MSP to DEN, a related route77.8%
- Alaska Airlines on-time record81.4%
- Delta Air Lines on-time record80.6%
- The best time of day to fly, according to 7.05 million flight records
- Worst months to fly in the US, ranked by the data
Direction matters. MSP to SEA and SEA to MSP are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
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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.