Route reliability record
JNU→SEA
Juneau to Seattle
- Flights
- 1,591
- Period
- July 2025 to June 2026
- Distance
- 909 mi
- Carriers
- 2
This route lands a B, 3 points better than the national rate of 77.6%. About one flight in five arrives 15 minutes late or worse, and those flights are late by about an hour on average. That is a workable record, not a spotless one. That rests on 1,591 JNU to SEA flights, with a median arrival 5 minutes early.
Best time to fly JNU to SEA: a 8pm–5am departure, ideally on a Sunday. Flights in that window arrived on time 83.2% of the time and Sunday flights 83.1%, against 80.3% for the route overall.
The US average over the same twelve months is 77.6%, 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
80.3%
Arrivals under 15 minutes late, of 1,559 completed flights
Avg delay
61 min
Across delayed arrivals only, not all flights
Cancelled
1.95%
National rate is 1.81%
Best carrier
Alaska
79.1% on time across 1,450 flights
These figures cover 1,591 flights between July 2025 and June 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.
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% | 122 min | 0.71% | A+ |
| Alaska Airlines | 1,450 | 79.1% | 59 min | 2.07% | 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.
Departure window
The best time of day to leave
Departure time is the single lever a traveller controls, and it moves the odds more than most people expect. Each bar below is the on-time rate for flights scheduled to leave inside that window, across 1,591 flights.
- 5am–8am646 flights82.3%
- 8am–11am—
- 11am–2pm144 flights77.5%
- 2pm–5pm334 flights76.0%
- 5pm–8pm366 flights81.1%
- 8pm–5am101 flights83.2%
Scale runs 70% to 90%. Rows with fewer than 30 flights show a dash.
The 8pm–5am window is the strongest at 83.2% on time. The full set of windows spans 7 points.
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 217 flights.
Across the week, Sunday is the strongest day at 83.1% on time and Friday the weakest at 77.8%. 5 points is a smaller lever than departure hour, but it is free.
Delay causes
Why this route gets delayed
One category carries most of the weight here. Carrier accounts for 43% of the 19,000 delay minutes carriers reported, and the remaining four split what is left. The split is by minutes rather than by flights, so a few very long delays count for as much as many short ones.
- 43%Carrier
- 31%Late-arriving aircraft
- 20%National Airspace System
- 6%Extreme weather
- 1%Security
The largest share of delay minutes, 43%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. Unlike weather, that is a management outcome, and it is the category where the gap between two carriers on the same schedule is genuinely earned. It accounts for 8,069 of the 19,000 delay minutes reported here. The split is drawn from 18,813 reported delay minutes.
Cancellations sit at 1.95% against a national 1.81%, which is ordinary. Diversions add another 0.06%.
Connections and stage length
What a delay here actually costs
Badly late arrivals are rare here: only 4.7% land an hour or more behind schedule, against 8.1% 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. It is also long enough that the aircraft usually flies three or four legs a day rather than six, which slows how fast delay compounds.
The return leg is a different operation and performs like one: it runs 76.6% on time across 1,589 flights, 4 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 4 points of difference.
The sample behind these figures is 1,591 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. 1,559 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 19.7% of the 1,591 flights in this analysis, against 22.4% nationally. Delayed flights are late by about an hour on average.
How reliable is JNU to SEA compared with the rest of the country?
80.3% of flights arrive on time here against a national 77.6%, a difference of 3 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 83.2% on time. The 2pm–5pm window is the weakest at 76.0%, 7 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 SEA79.1%
- JNU to ANC, a related route83.1%
- LAX to SEA, a related route85.4%
- JNU to SIT, a related route84.0%
- Delta Air Lines on-time record92.1%
- Alaska Airlines on-time record79.1%
- Worst months to fly in the US, ranked by the data
- US airports with the biggest gap between their best and worst month
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, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.