Route reliability record
SEA→ANC
Seattle to Anchorage
- Flights
- 6,619
- Period
- September 2025 to August 2026
- Distance
- 1,448 mi
- Carriers
- 3
This route lands a B+, about a point worse than the national rate of 77.3%. About one flight in four arrives 15 minutes late or worse, and those flights are late by about 50 minutes on average. That rests on 6,619 SEA to ANC flights, of which Delta Air Lines flew 1,609 at 77.5% on time.
Best time to fly SEA to ANC: a 5am–8am departure, ideally on a Tuesday. Flights in that window arrived on time 90.7% of the time and Tuesday flights 79.5%, against 76.5% 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
76.5%
Arrivals under 15 minutes late, of 6,567 completed flights
Avg delay
50 min
Across delayed arrivals only, not all flights
Cancelled
0.71%
National rate is 1.89%
Best carrier
Delta
77.5% on time across 1,609 flights
These figures cover 6,619 flights between September 2025 and August 2026. The median arrival is 2 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 SEA to ANC
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 |
|---|---|---|---|---|---|
| Delta Air Lines | 1,609 | 77.5% | 62 min | 0.62% | B+ |
| Alaska Airlines | 4,999 | 76.3% | 47 min | 0.74% | B+ |
| Hawaiian Airlinesthin sample | 11 | 54.5% | 32 min | 0.00% | F+ |
No carrier stands out. Delta tops the table at 77.5%, 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 SEA to ANC
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 Seattle to Anchorage
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. SEA → ANCSeattle to Anchorage | Delta Air Lines | 77.0% | 77.5% | 0.62% | 5am–8am, Sat | DL 922 10:35 |
| 2. SEA → ANCSeattle to Anchorage | Alaska Airlines | 75.7% | 76.3% | 0.74% | 5am–8am, Tue | AS 99 15:58 |
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 17 points, against about a point between the best and worst carrier.
- 5am–8am447 flights90.7%
- 8am–11am1,245 flights78.7%
- 11am–2pm1,238 flights73.8%
- 2pm–5pm673 flights77.7%
- 5pm–8pm1,160 flights73.4%
- 8pm–5am1,856 flights75.1%
Scale runs 65% to 95%.
Book the early departure. Flights leaving between 5am–8am arrive on time 90.7% of the time, against 73.4% for the evening window. That is 17 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 1,856 flights scheduled in it.
Explore
Filter SEA to ANC 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 SEA to ANC, the best departure window is 5am–8am at 90.7% on time and the worst is 5pm–8pm at 73.4%, a wide gap of 17.3 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am90.7%
- 8–11am78.7%
- 11am–2pm73.8%
- 2–5pm77.7%
- 5–8pm73.4%
- 8pm–5am75.1%
best all US flightsScale 60% to 95%.
Across the year
When delays peak on this route
This route's year swings by 34 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 54.6% on time, against 88.4% in September. 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.
Across the week, Tuesday is the strongest day at 79.5% on time and Thursday the weakest at 72.2%, a spread of 7 points.
Delay causes
Why this route gets delayed
Carrier accounts for 49% of the 77,000 delay minutes carriers reported here, and the remaining four split what is left.
- 49%Carrier
- 29%Late-arriving aircraft
- 19%National Airspace System
- 3%Extreme weather
- 0%Security
The largest share of delay minutes, 49%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 38,000 of the 77,000 delay minutes reported here. The split is drawn from 77,409 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 90.7% on time here.
Cancellations are rare at 0.71%, 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
5.1% 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 50 minutes, which a normal layover absorbs.
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 86.9% on time across 6,616 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.
The sample behind these figures is 6,619 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 ANC 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. September runs 88.4% on time and December 54.6%, a swing of 34 points. If the dates move at all, move them out of December before you think about anything else. 6,567 completed flights over 12 months sit behind that.
Common questions
SEA to ANC questions
How often is SEA to ANC delayed?
About one flight in four arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 23.5% of the 6,619 flights in this analysis, against 22.7% nationally. Delayed flights are late by about 50 minutes on average.
Which airline is most reliable on SEA to ANC?
Delta Air Lines leads at 77.5% on time across 1,609 flights. Alaska Airlines is at the other end on 76.3%, 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 SEA to ANC?
The 5am–8am departure window is the strongest at 90.7% on time. The 5pm–8pm window is the weakest at 73.4%, 17 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 SEA to ANC?
December is the weakest month at 54.6% on time, compared with 88.4% in September. Across the year that is 34 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
- ANC to SEA — the return legseparate record
- Seattle-Tacoma International (SEA) delay statistics
- Delta Air Lines on SEA to ANC77.5%
- Alaska Airlines on SEA to ANC76.3%
- SEA to LAX, a related route82.0%
- FAI to ANC, a related route86.1%
- SEA to PHX, a related route78.2%
- Delta Air Lines on-time record77.5%
- Alaska Airlines on-time record76.3%
- Hawaiian Airlines on-time record54.5%
- 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. SEA to ANC and ANC to SEA 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.