Route reliability record
JFK→SEA
New York to Seattle
- Flights
- 2,906
- Period
- September 2025 to August 2026
- Distance
- 2,422 mi
- Carriers
- 3
This route carries a cancellation problem, not just a delay problem: 3.4% of scheduled flights never operate, against 1.9% nationally. Of the ones that do fly, about seven flights in ten arrive on time, worth a C− overall. The punctuality figure counts only flights that actually departed, so it flatters an operation that cancels this often. That rests on 2,906 JFK to SEA flights, of which Delta Air Lines flew 1,339 at 71.4% on time.
Best time to fly JFK to SEA: a 11am–2pm departure, ideally on a Wednesday. Flights in that window arrived on time 80.1% of the time and Wednesday flights 73.3%, against 69.5% for the route overall.
The national on-time rate over the same period is 77.3%, so this route runs 8 points behind the country as a whole. Across a thousand flights that is about 78 extra late arrivals.
Key figures
On time
69.5%
Arrivals under 15 minutes late, of 2,797 completed flights
Avg delay
65 min
Across delayed arrivals only, not all flights
Cancelled
3.44%
National rate is 1.89%
Best carrier
Delta
71.4% on time across 1,339 flights
These figures cover 2,906 flights between September 2025 and August 2026. Beyond the headline rate, 9.7% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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Carrier by carrier
Which airline is most reliable on JFK to SEA
The two carriers here are closely matched: 3 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 | 1,339 | 71.4% | 60 min | 3.21% | C− |
| Alaska Airlines | 1,401 | 68.1% | 65 min | 3.35% | C− |
| JetBlue Airwaysthin sample | 166 | 65.4% | 94 min | 6.02% | C− |
Alaska Airlines cancels 3.4% of what it schedules here, the highest in the table. A cancelled flight never appears in an on-time rate, so read that column alongside the punctuality one rather than after it.
Flight by flight
Flights on JFK 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 New York to Seattle
Every airline on this route and on the routes between nearby airports, ranked by how often a scheduled flight actually operated and arrived on time. 2 of the top 4 use a different airport at one end.
| Option | Airline | Success | On time | Cancelled | Best departure | Most punctual flight |
|---|---|---|---|---|---|---|
| 1. EWR → SEANewark to Seattle | United Airlines | 73.1% | 74.5% | 1.82% | 5am–8am, Sat | UA 1330 08:50 |
| 2. EWR → SEANewark to Seattle | Alaska Airlines | 69.6% | 71.6% | 2.83% | 8am–11am, Thu | AS 299 07:25 |
| 3. JFK → SEANew York to Seattle | Delta Air Lines | 69.1% | 71.4% | 3.21% | 11am–2pm, Fri | DL 699 07:00 |
| 4. JFK → SEANew York to Seattle | Alaska Airlines | 65.8% | 68.1% | 3.35% | 11am–2pm, Sat | AS 23 11:30 |
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 18 points, against 3 points between the best and worst carrier.
- 5am–8am686 flights71.6%
- 8am–11am39 flights75.7%
- 11am–2pm578 flights80.1%
- 2pm–5pm551 flights68.7%
- 5pm–8pm942 flights62.4%
- 8pm–5am110 flights62.3%
Scale runs 55% to 85%.
The 8pm–5am window is where this operation falls apart: 62.3% on time, against 80.1% for the 11am–2pm slot. By evening the aircraft flying these rotations have absorbed a full day of small delays and there is no slack left to recover in. The 5pm–8pm window is the busiest, with 942 flights scheduled in it.
Explore
Filter JFK 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 JFK to SEA, the best departure window is 11am–2pm at 80.1% on time and the worst is 8pm–5am at 62.3%, a wide gap of 17.8 points. All US flights leaving 11am–2pm ran 78.3%.
- 5–8am71.6%
- 8–11am75.7%
- 11am–2pm80.1%
- 2–5pm68.7%
- 5–8pm62.4%
- 8pm–5am62.3%
best all US flightsScale 55% to 95%.
Across the year
When delays peak on this route
This route's year swings by 46 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 38.2% on time, against 83.9% 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 279 flights.
Across the week, Wednesday is the strongest day at 73.3% on time and Sunday the weakest at 64.0%, a spread of 9 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 55,000 reported delay minutes.
- 40%National Airspace System
- 29%Carrier
- 23%Late-arriving aircraft
- 8%Extreme weather
- 1%Security
40% of delay minutes are charged to the National Airspace System: air traffic volume, runway configuration, ground stops. No carrier can price its way out of that, which is why airport choice moves the number here more than carrier choice does. That is 22,000 minutes out of 55,000, against a national NAS share of 21%. The split is drawn from 54,997 reported delay minutes.
Cancellations run at 3.44%, against 1.89% nationally. That is about one flight in 30 cancelled outright. A cancelled flight is invisible in every on-time figure on this page, so the punctuality numbers above describe only the flights that actually operated.
Connections and stage length
What a delay here actually costs
9.7% of arrivals land a full hour or more behind schedule, against 8.3% nationally. Ninety minutes is the honest minimum for a connection here, and two hours if the onward flight is on a separate ticket.
At 2,422 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 is a different operation and performs like one: it runs 78.0% on time across 2,906 flights, 9 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 9 points of difference.
The sample behind these figures is 2,906 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 delay figures matter less here than the 3.44% cancellation rate. A late arrival costs you about an hour; a cancelled flight costs you the day. Book the 11am–2pm departure so there is still a schedule behind you if it goes wrong, and treat a same-day connection as optimistic. 2,797 completed flights over 12 months sit behind that.
Common questions
JFK to SEA questions
How often is JFK to SEA delayed?
Roughly one flight in three arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 30.5% of the 2,906 flights in this analysis, against 22.7% nationally. Delayed flights are late by about an hour on average.
Which airline is most reliable on JFK to SEA?
Delta Air Lines leads at 71.4% on time across 1,339 flights. Alaska Airlines is at the other end on 68.1%, a gap of 3 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 JFK to SEA?
The 11am–2pm departure window is the strongest at 80.1% on time. The 8pm–5am window is the weakest at 62.3%, 18 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 JFK to SEA?
December is the weakest month at 38.2% on time, compared with 83.9% in September. Across the year that is 46 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 JFK — the return legseparate record
- John F. Kennedy International (JFK) delay statistics
- Seattle-Tacoma International (SEA) delay statistics
- Delta Air Lines on JFK to SEA71.4%
- Alaska Airlines on JFK to SEA68.1%
- JetBlue Airways on JFK to SEA65.4%
- JFK to LAX, a related route75.4%
- LAX to SEA, a related route85.0%
- JFK to SFO, a related route71.4%
- Delta Air Lines on-time record71.4%
- Alaska Airlines on-time record68.1%
- JetBlue Airways on-time record65.4%
- The US routes with the most cancellations
- What a cancellation rate actually tells you (and what it hides)
Direction matters. JFK to SEA and SEA to JFK 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.