Route reliability record
AUS→SEA
Austin to Seattle
- Flights
- 2,089
- Period
- September 2025 to August 2026
- Distance
- 1,770 mi
- Carriers
- 3
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 2,089 AUS to SEA flights, of which Delta Air Lines flew 949 at 83.8% on time.
Best time to fly AUS to SEA: a 5am–8am departure, ideally on a Saturday. Flights in that window arrived on time 89.9% of the time and Saturday flights 87.5%, against 81.3% for the route overall.
Set against the rest of the country, this route's record is 4 points better than the US average of 77.3%. That gap is worth roughly 40 fewer late arrivals for every thousand flights.
Key figures
On time
81.3%
Arrivals under 15 minutes late, of 2,067 completed flights
Avg delay
61 min
Across delayed arrivals only, not all flights
Cancelled
0.86%
National rate is 1.89%
Best carrier
Delta
83.8% on time across 949 flights
These figures cover 2,089 flights between September 2025 and August 2026. The median arrival is 7 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 AUS 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 | 949 | 83.8% | 82 min | 0.95% | B+ |
| Alaska Airlines | 1,051 | 81.8% | 50 min | 0.76% | B+ |
| Southwest Airlinesthin sample | 89 | 48.9% | 38 min | 1.12% | F |
No carrier stands out. Delta tops the table at 83.8%, 2 points clear of the bottom, which is inside the range this kind of sample moves year to year.
Flight by flight
Flights on AUS 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 Austin 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. AUS → SEAAustin to Seattle | Delta Air Lines | 83.0% | 83.8% | 0.95% | 5am–8am, Sat | DL 780 06:00 |
| 2. AUS → SEAAustin to Seattle | Alaska Airlines | 81.2% | 81.8% | 0.76% | 5am–8am, Sat | AS 503 16:17 |
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 16 points, against 2 points between the best and worst carrier.
- 5am–8am543 flights89.9%
- 8am–11am171 flights83.0%
- 11am–2pm443 flights83.1%
- 2pm–5pm265 flights78.9%
- 5pm–8pm643 flights73.5%
- 8pm–5am24 flights—
Scale runs 65% to 95%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 89.9% of the time, against 73.5% 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 5pm–8pm window is the busiest, with 643 flights scheduled in it.
Explore
Filter AUS 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 AUS to SEA, the best departure window is 5am–8am at 89.9% on time and the worst is 5pm–8pm at 73.5%, a wide gap of 16.4 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am89.9%
- 8–11am83.0%
- 11am–2pm83.1%
- 2–5pm78.9%
- 5–8pm73.5%
- 8pm–5am—
best all US flightsScale 60% to 95%. Cells under 30 flights show a dash.
Across the year
When delays peak on this route
This route's year swings by 22 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 70.2% on time, against 91.8% 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 217 flights.
Across the week, Saturday is the strongest day at 87.5% on time and Thursday the weakest at 75.6%, a spread of 12 points.
Delay causes
Why this route gets delayed
Carriers report a reason for every delay minute they cause, in five DOT categories. The split below is by minutes, not by number of flights, so a handful of very long weather delays weighs as much as many short ones. It covers 24,000 reported delay minutes.
- 42%Late-arriving aircraft
- 35%Carrier
- 18%National Airspace System
- 5%Extreme weather
- 1%Security
42% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 24,000 reported delay minutes here, that single category outweighs weather by 9 to one. The split is drawn from 23,607 reported delay minutes.
The largest share of delay minutes, 35%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 8,180 of the 24,000 delay minutes reported here.
Cancellations are rare at 0.86%, 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
5.5% 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.
At 1,770 miles this is transcontinental flying, and long routes get a quiet structural advantage. Scheduled block time on a flight this length carries more padding in absolute minutes, so a twenty-minute late departure often still becomes an on-time arrival. Read the on-time rate here as slightly flattering next to a short-haul route with the same operational quality.
The return leg runs 78.5% on time across 2,090 flights, within 3 points of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.
The sample behind these figures is 2,089 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 91.8% on time and December 70.2%, a swing of 22 points. If the dates move at all, move them out of December before you think about anything else. 2,067 completed flights over 12 months sit behind that.
Common questions
AUS to SEA questions
How often is AUS 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 18.7% of the 2,089 flights in this analysis, against 22.7% nationally. Delayed flights are late by about an hour on average.
Which airline is most reliable on AUS to SEA?
Delta Air Lines leads at 83.8% on time across 949 flights. Alaska Airlines is at the other end on 81.8%, 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 AUS to SEA?
The 5am–8am departure window is the strongest at 89.9% on time. The 5pm–8pm window is the weakest at 73.5%, 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 December delays on AUS to SEA?
December is the weakest month at 70.2% on time, compared with 91.8% in April. Across the year that is 22 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 AUS — the return legseparate record
- Austin-Bergstrom International (AUS) delay statistics
- Seattle-Tacoma International (SEA) delay statistics
- Delta Air Lines on AUS to SEA83.8%
- Alaska Airlines on AUS to SEA81.8%
- AUS to DEN, a related route78.9%
- LAX to SEA, a related route85.0%
- AUS to DFW, a related route74.9%
- Delta Air Lines on-time record83.8%
- Alaska Airlines on-time record81.8%
- Southwest Airlines on-time record48.9%
- 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. AUS to SEA and SEA to AUS 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.