Route reliability record
ANC→SEA
Anchorage to Seattle
- Flights
- 6,616
- Period
- September 2025 to August 2026
- Distance
- 1,448 mi
- Carriers
- 3
This route earns an 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 10 points better than the national rate of 77.3%. When something does go wrong the average delay runs about an hour. That rests on 6,616 ANC to SEA flights, of which Delta Air Lines flew 1,608 at 88.7% on time.
Best time to fly ANC to SEA: a 8am–11am departure, ideally on a Saturday. Flights in that window arrived on time 91.0% of the time and Saturday flights 88.5%, against 86.9% for the route overall.
Set against the rest of the country, this route's record is 10 points better than the US average of 77.3%. That gap is worth roughly 96 fewer late arrivals for every thousand flights.
Key figures
On time
86.9%
Arrivals under 15 minutes late, of 6,555 completed flights
Avg delay
64 min
Across delayed arrivals only, not all flights
Cancelled
0.85%
National rate is 1.89%
Best carrier
Delta
88.7% on time across 1,608 flights
These figures cover 6,616 flights between September 2025 and August 2026. The median arrival is 12 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 ANC to SEA
The two carriers here are closely matched: 2 points 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 |
|---|---|---|---|---|---|
| Delta Air Lines | 1,608 | 88.7% | 104 min | 0.68% | A+ |
| Alaska Airlines | 4,997 | 86.4% | 54 min | 0.90% | A+ |
| Hawaiian Airlinesthin sample | 11 | 27.3% | 34 min | 0.00% | F+ |
No carrier stands out. Delta tops the table at 88.7%, 2 points clear of the bottom, which is inside the range this kind of sample moves year to year.
Flight by flight
Flights on ANC 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 Anchorage 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. ANC → SEAAnchorage to Seattle | Delta Air Lines | 88.1% | 88.7% | 0.68% | 8am–11am, Fri | DL 925 01:30 |
| 2. ANC → SEAAnchorage to Seattle | Alaska Airlines | 85.6% | 86.4% | 0.90% | 8am–11am, Sat | AS 48 08:00 |
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 12 points, against 2 points between the best and worst carrier.
- 5am–8am1,246 flights87.6%
- 8am–11am909 flights91.0%
- 11am–2pm960 flights89.1%
- 2pm–5pm1,071 flights81.0%
- 5pm–8pm724 flights79.3%
- 8pm–5am1,706 flights89.8%
Scale runs 70% to 95%.
Book the morning departure. Flights leaving between 8am–11am arrive on time 91.0% of the time, against 79.3% for the evening window. That is 12 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 8pm–5am window is the busiest, with 1,706 flights scheduled in it.
Explore
Filter ANC 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 ANC to SEA, the best departure window is 8am–11am at 91.0% on time and the worst is 5pm–8pm at 79.3%, a wide gap of 11.7 points. All US flights leaving 8am–11am ran 83.9%.
- 5–8am87.6%
- 8–11am91.0%
- 11am–2pm89.1%
- 2–5pm81.0%
- 5–8pm79.3%
- 8pm–5am89.8%
best all US flightsScale 60% to 95%.
Across the year
When delays peak on this route
This route's year swings by 16 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 78.9% on time, against 94.7% 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 721 flights.
The day of the week is close to irrelevant here: 3 points separates the best day from the worst. Weekly demand peaks are not what drives the delays on this operation.
Delay causes
Why this route gets delayed
Carrier accounts for 43% of the 55,000 delay minutes carriers reported here, and the remaining four split what is left.
- 43%Carrier
- 35%Late-arriving aircraft
- 13%National Airspace System
- 8%Extreme weather
- 0%Security
35% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 55,000 reported delay minutes here, that single category outweighs weather by 4 to one. The split is drawn from 54,992 reported delay minutes.
The largest share of delay minutes, 43%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 24,000 of the 55,000 delay minutes reported here.
Cancellations are rare at 0.85%, below the national 1.89% 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 3.8% land an hour or more behind schedule, against 8.3% 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 1,448 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 76.5% on time across 6,619 flights, 10 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 10 points of difference.
The sample behind these figures is 6,616 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 94.7% on time and December 78.9%, a swing of 16 points. If the dates move at all, move them out of December before you think about anything else. 6,555 completed flights over 12 months sit behind that.
Common questions
ANC to SEA questions
How often is ANC to SEA delayed?
About one flight in eight arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 13.1% of the 6,616 flights in this analysis, against 22.7% nationally. Delayed flights are late by about an hour on average.
Which airline is most reliable on ANC to SEA?
Delta Air Lines leads at 88.7% on time across 1,608 flights. Alaska Airlines is at the other end on 86.4%, a gap of 2 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 ANC to SEA?
The 8am–11am departure window is the strongest at 91.0% on time. The 5pm–8pm window is the weakest at 79.3%, 12 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 ANC to SEA?
December is the weakest month at 78.9% on time, compared with 94.7% in April. Across the year that is 16 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 ANC — the return legseparate record
- Seattle-Tacoma International (SEA) delay statistics
- Delta Air Lines on ANC to SEA88.7%
- Alaska Airlines on ANC to SEA86.4%
- ANC to FAI, a related route88.6%
- LAX to SEA, a related route85.0%
- ANC to PDX, a related route90.5%
- Delta Air Lines on-time record88.7%
- Alaska Airlines on-time record86.4%
- Hawaiian Airlines on-time record27.3%
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.05 million flight records
Direction matters. ANC to SEA and SEA to ANC 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.