Route reliability record
JNU→SEA
Juneau to Seattle
- Flights
- 1,589
- Period
- September 2025 to August 2026
- Distance
- 909 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 1,589 JNU to SEA flights, with a median arrival 6 minutes early.
Best time to fly JNU to SEA: a 8pm–5am departure, ideally on a Friday. Flights in that window arrived on time 90.6% of the time and Friday flights 83.8%, against 81.4% 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 41 fewer late arrivals for every thousand flights.
Key figures
On time
81.4%
Arrivals under 15 minutes late, of 1,560 completed flights
Avg delay
61 min
Across delayed arrivals only, not all flights
Cancelled
1.83%
National rate is 1.89%
Best carrier
Alaska
80.4% on time across 1,448 flights
These figures cover 1,589 flights between September 2025 and August 2026. The median arrival is 6 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 JNU to SEA
Only one carrier clears this site's 365-flight floor here, so there is no comparison to draw. The table below is the full picture.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Delta Air Linesthin sample | 141 | 92.1% | 114 min | 1.42% | A |
| Alaska Airlines | 1,448 | 80.4% | 58 min | 1.86% | B |
Flight by flight
Flights on JNU 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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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 20 points, against half a point between the best and worst carrier.
- 5am–8am646 flights82.8%
- 8am–11am—
- 11am–2pm144 flights70.4%
- 2pm–5pm334 flights77.8%
- 5pm–8pm366 flights84.2%
- 8pm–5am99 flights90.6%
Scale runs 60% to 95%. Rows with fewer than 30 flights show a dash.
The weak window here is the middle of the day, not the evening: 11am–2pm runs 70.4% on time against 90.6% for 8pm–5am. That shape usually means a departure bank rather than an accumulating delay, so the recovery later in the afternoon is real rather than noise. The 5am–8am window is the busiest, with 646 flights scheduled in it.
Explore
Filter JNU 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 JNU to SEA, the best departure window is 8pm–5am at 90.6% on time and the worst is 11am–2pm at 70.4%, a wide gap of 20.2 points. All US flights leaving 8pm–5am ran 70.1%.
- 5–8am82.8%
- 8–11am—
- 11am–2pm70.4%
- 2–5pm77.8%
- 5–8pm84.2%
- 8pm–5am90.6%
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.
April is the best month on the calendar at 91.1% on time. Shoulder season thins the schedule and takes the summer weather with it, and the operation gets its margin back. July was the busiest month here, with 216 flights.
Across the week, Friday is the strongest day at 83.8% on time and Tuesday the weakest at 79.3%, a spread of 5 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 18,000 reported delay minutes.
- 41%Carrier
- 32%Late-arriving aircraft
- 19%National Airspace System
- 6%Extreme weather
- 1%Security
The largest share of delay minutes, 41%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 7,237 of the 18,000 delay minutes reported here. The split is drawn from 17,549 reported delay minutes.
Cancellations sit at 1.83% against a national 1.89%, which is ordinary. Diversions add another 0.00%.
Connections and stage length
What a delay here actually costs
Badly late arrivals are rare here: only 4.6% 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 909 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 runs 79.2% on time across 1,588 flights, within 2 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 1,589 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 91.1% on time and March 69.2%, a swing of 22 points. If the dates move at all, move them out of March before you think about anything else. 1,560 completed flights over 12 months sit behind that.
Common questions
JNU to SEA questions
How often is JNU 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 18.6% of the 1,589 flights in this analysis, against 22.7% nationally. Delayed flights are late by about an hour on average.
How reliable is JNU to SEA compared with the rest of the country?
81.4% of flights arrive on time here against a national 77.3%, a difference of 4 points in its favour. That is worth a B on this site's grading scale.
What time of day has the fewest delays on JNU to SEA?
The 8pm–5am departure window is the strongest at 90.6% on time. The 11am–2pm window is the weakest at 70.4%, 20 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 March delays on JNU to SEA?
March is the weakest month at 69.2% on time, compared with 91.1% 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 JNU — the return legseparate record
- Seattle-Tacoma International (SEA) delay statistics
- Delta Air Lines on JNU to SEA92.1%
- Alaska Airlines on JNU to SEA80.4%
- JNU to ANC, a related route84.2%
- LAX to SEA, a related route85.0%
- JNU to SIT, a related route85.0%
- Delta Air Lines on-time record92.1%
- Alaska Airlines on-time record80.4%
- 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. JNU to SEA and SEA to JNU 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.