Route profile
SFO→SEA
Flight reliability, delays and best times to fly from San Francisco to Seattle, 679 miles.
Right now
Aviation weather is not currently a factor.
Aviation weather is not currently a factor.
Route reliability
July 2023 – July 2026
Better than 49% of comparable major US routes (4,598 compared)
Calculated from 20,767 flights. How this is calculated
SFO → SEA arrives on time 75.9% of the time; the return trip, SEA → SFO, arrives on time 68.7% of the time, a 7.2-point gap between the two directions of the same city pair.
SFO → SEA spends 33.2 minutes on the ground on a 679-mile trip: 21.7 minutes from pushback to wheels-up at SFO and 11.6 minutes from touchdown to gate at SEA.
Source: US DOT Bureau of Transportation Statistics · Data covering July 2023 – July 2026
Why SFO → SEA flights are cancelled
July 2023 – July 2026
SFO → SEA cancelled 240 of 20,767 scheduled flights — about 1 in every 87. The reason filed most often was the airline, 75.4% of the cancellations coded on this route — about 1 in every 115 scheduled flights.
Share of cancellations
Of 240 cancelled departures carrying a reason code.
What each reason means
Crew, maintenance, aircraft cleaning, baggage or fueling: what BTS counts as within the carrier’s own control.
181 cancellations, 75.4% of the total.
Conditions the carrier judged severe enough to stop the flight: a blizzard, a hurricane, a line of thunderstorms.
40 cancellations, 16.7% of the total.
Airport capacity, air traffic control flow programs, heavy traffic and ordinary bad weather. A system decision, not the airline’s.
19 cancellations, 7.9% of the total.
A terminal evacuation, a security breach, screening equipment failure, or screening queues over 29 minutes.
0 cancellations, 0.0% of the total.
Reason codes are the operating airline’s own filing with US DOT, not an independent finding of fault. Ordinary bad weather is filed under air traffic, so weather’s full share is larger than its bar.
240 coded cancellations were recorded on SFO → SEA; the section appears from 50.
When it goes wrong
July 2023 – July 2026
44 min late
against a median of 5 min early
Percentiles over 20,767 operations; cancelled and diverted flights are counted separately.
Will your connection be tight enough?
Layovers at SEA after arriving from SFO.
| Connection time | Chance of missing | Reads as |
|---|---|---|
| 30 min | 40% | Likely to miss |
| 45 min | 23% | High risk |
| 60 min | 14% | Some risk |
| 90 min | 6.7% | Some risk |
| 120 min | 3.6% | Low risk |
This is one leg of a connection. Gate changes and the next flight's own schedule matter too. And a connection can fail before delay is even the question — this route cancels 1.16% of the time and diverts 0.06% of the time, which a late arrival never shows up in.
Chance of missing is the share of 20,515 arrivals on this route that landed later than the connection time less 30 minutes to reach the next gate.
The worst tenth of arrivals on this route land at least 44 minutes late (90th-percentile gate arrival delay), over 20,767 operations.
Any other layover length: connection checker.
Best time to fly
SFO → SEA flights departing 5–9 AM arrived on time 85.6% of the time, against 69.4% for 6–9 PM departures, a gap of 16.2 percentage points.
By day and hour
On-time arrival rate for each weekday and scheduled departure hour, in local time at the departure airport (SFO).
Hour of departure matters more than day of the week: hourly averages sit a typical 8.2 points from the route-wide rate, weekday averages 3.3 points.
| Hour | Monday | Tuesday | Wednesday | Thursday | Friday | Saturday | Sunday |
|---|---|---|---|---|---|---|---|
| 6 AM–7 AM | |||||||
| 7 AM–8 AM | |||||||
| 8 AM–9 AM | |||||||
| 9 AM–10 AM | |||||||
| 10 AM–11 AM | |||||||
| 11 AM–12 PM | |||||||
| 12 PM–1 PM | |||||||
| 1 PM–2 PM | |||||||
| 2 PM–3 PM | |||||||
| 3 PM–4 PM | |||||||
| 4 PM–5 PM | |||||||
| 5 PM–6 PM | |||||||
| 6 PM–7 PM | |||||||
| 7 PM–8 PM | |||||||
| 8 PM–9 PM | |||||||
| 9 PM–10 PM | |||||||
| 10 PM–11 PM |
On-time rate, % · stronger color, fewer on time
- 50–59
- 60–69
- 70–79
- 80–89
- 90–99
- Fewer than 120 flights, not scored
Source: FlyerIntel analysis of US DOT BTS data · July 2023 – July 2026 · On time is arrival within 15 minutes of schedule. Cells round to whole percentages; the table shows one decimal.
No slot is named best or worst: too few reach 500 flights. Departures before 6 AM and after 11 PM (461 flights) are not drawn: no slot in those hours has enough flights to score.
View as tableHide table
| Hour | Monday | Tuesday | Wednesday | Thursday | Friday | Saturday | Sunday |
|---|---|---|---|---|---|---|---|
| 6 AM–7 AM | 94.2% on time262 flights | 91.4% on time220 flights | 94.9% on time220 flights | 93.2% on time241 flights | 94.5% on time255 flights | 92.3% on time224 flights | 93.6% on time272 flights |
| 7 AM–8 AM | 119 flights, too few to score | 91 flights, too few to score | 86 flights, too few to score | 90.6% on time128 flights | 86.0% on time122 flights | 49 flights, too few to score | 100 flights, too few to score |
| 8 AM–9 AM | 55.1% on time137 flights | 62.9% on time132 flights | 63.0% on time128 flights | 66.7% on time137 flights | 66.4% on time122 flights | 76 flights, too few to score | 66.4% on time126 flights |
| 9 AM–10 AM | 80.8% on time217 flights | 86.9% on time216 flights | 83.3% on time216 flights | 83.3% on time208 flights | 75.1% on time222 flights | 88.2% on time170 flights | 82.1% on time199 flights |
| 10 AM–11 AM | 69.6% on time269 flights | 77.4% on time260 flights | 74.8% on time266 flights | 71.3% on time269 flights | 67.1% on time264 flights | 75.5% on time232 flights | 73.9% on time234 flights |
| 11 AM–12 PM | 76.3% on time136 flights | 80.8% on time131 flights | 83.5% on time131 flights | 76.6% on time133 flights | 79.2% on time130 flights | 105 flights, too few to score | 71.5% on time132 flights |
| 12 PM–1 PM | 63.4% on time182 flights | 79.1% on time179 flights | 73.7% on time182 flights | 66.9% on time179 flights | 67.4% on time178 flights | 68.0% on time123 flights | 70.2% on time171 flights |
| 1 PM–2 PM | 81.8% on time209 flights | 83.2% on time197 flights | 79.9% on time199 flights | 82.0% on time207 flights | 81.0% on time207 flights | 84.4% on time175 flights | 77.8% on time214 flights |
| 2 PM–3 PM | 66.7% on time189 flights | 80.9% on time183 flights | 68.0% on time183 flights | 67.9% on time191 flights | 66.7% on time184 flights | 80.6% on time139 flights | 69.4% on time174 flights |
| 3 PM–4 PM | 21 flights, too few to score | 21 flights, too few to score | 21 flights, too few to score | 23 flights, too few to score | 26 flights, too few to score | 45 flights, too few to score | 34 flights, too few to score |
| 4 PM–5 PM | 72.6% on time414 flights | 82.5% on time388 flights | 74.6% on time390 flights | 72.5% on time405 flights | 71.7% on time403 flights | 84.5% on time307 flights | 70.3% on time383 flights |
| 5 PM–6 PM | 97 flights, too few to score | 99 flights, too few to score | 102 flights, too few to score | 95 flights, too few to score | 97 flights, too few to score | 89 flights, too few to score | 106 flights, too few to score |
| 6 PM–7 PM | 74.4% on time199 flights | 81.4% on time177 flights | 77.3% on time185 flights | 64.4% on time195 flights | 67.2% on time196 flights | 75.7% on time185 flights | 64.5% on time187 flights |
| 7 PM–8 PM | 59.2% on time195 flights | 75.1% on time178 flights | 69.8% on time180 flights | 59.5% on time187 flights | 54.9% on time188 flights | 76.9% on time188 flights | 62.6% on time193 flights |
| 8 PM–9 PM | 67.1% on time214 flights | 77.1% on time176 flights | 71.6% on time176 flights | 71.5% on time208 flights | 65.7% on time207 flights | 78.0% on time174 flights | 65.9% on time219 flights |
| 9 PM–10 PM | 113 flights, too few to score | 77 flights, too few to score | 78 flights, too few to score | 117 flights, too few to score | 108 flights, too few to score | 87 flights, too few to score | 112 flights, too few to score |
| 10 PM–11 PM | 61.2% on time121 flights | 118 flights, too few to score | 79.5% on time123 flights | 115 flights, too few to score | 111 flights, too few to score | 107 flights, too few to score | 114 flights, too few to score |
By departure window
By departure hour
- 12 AM to 4 AM: too few flights to score
- 5 AM: 95.6% on time from 459 flights
- 6 AM: 93.5% on time from 1,694 flights
- 7 AM: 88.5% on time from 695 flights
- 8 AM: 62.7% on time from 858 flights
- 9 AM: 82.6% on time from 1,448 flights
- 10 AM: 72.7% on time from 1,794 flights
- 11 AM: 78.2% on time from 898 flights
- 12 PM: 69.9% on time from 1,194 flights
- 1 PM: 81.4% on time from 1,408 flights
- 2 PM: 71.1% on time from 1,243 flights
- 3 PM: 65.1% on time from 191 flights
- 4 PM: 75.2% on time from 2,690 flights
- 5 PM: 74.7% on time from 685 flights
- 6 PM: 72.0% on time from 1,324 flights
- 7 PM: 65.3% on time from 1,309 flights
- 8 PM: 70.6% on time from 1,374 flights
- 9 PM: 70.9% on time from 692 flights
- 10 PM: 73.8% on time from 809 flights
- 11 PM: too few flights to score
Why SFO → SEA runs late
July 2023 – July 2026
the inbound aircraft was late, so this flight started late
crew, maintenance, boarding and fueling, all within the carrier’s control
airspace and airport capacity, including weather-driven flow control
weather severe enough to stop this flight specifically
screening or terminal security incidents
Share of the delay minutes US DOT attributed to each cause for SFO → SEA. Only delays of 15 minutes or more are attributed.
Late-arriving aircraft is the largest cause on SFO → SEA, at 46.3%: flights here mostly leave late because the plane came in late, and the day shows it: 5–9 AM departures arrived on time 85.6% of the time and 6–9 PM departures 69.4%.
How this route holds up in bad weather
July 2023 – July 2026
Bad weather raises cancellations by a similar amount at both ends of SFO to SEA: 1.7 times the normal rate at SFO and 1.9 times at SEA. Cancelled in bad weather against normal hours: SFO 1.5% against 0.9%, SEA 1.5% against 0.8%. Flights that did leave SFO in bad weather arrived on time 73.0% of the time, against 79.8% in normal hours.
Bad weather and normal hours at the airports
Scheduled departures, July 2023 – July 2026| Departures from | SFO | SEA |
|---|---|---|
| Cancelled in bad weather | 1.5% | 1.5% |
| Cancelled in normal hours | 0.9% | 0.8% |
| Arrived on time, bad weather | 73.0% | 75.4% |
| Arrived on time, normal hours | 79.8% | 79.3% |
| Departures in bad weather | 36,006 | 43,416 |
Of the carriers on this route, United Airlines (1.0% cancelled against 1.9% for the other carriers at SFO) cancelled the fewest departures from SFO in bad weather and SkyWest Airlines (3.0% cancelled against 1.2% for the other carriers at SFO) the most.
This route’s airlines in bad weather at SFO
All departures from SFO| Airline | Bad-weather departures | Cancelled | Other carriers |
|---|---|---|---|
| United Airlines | 13,903 | 1.0%below the others | 1.9% |
| Delta Air Lines | 3,513 | 0.8%below the others | 1.5% |
| Alaska Airlines | 3,124 | 1.8%about level | 1.4% |
| SkyWest Airlines | 7,724 | 3.0%above the others | 1.2% |
These are airport figures, not route figures: every scheduled departure from SFO and SEA, to any destination, in hours the weather report called bad. The airline rows count each carrier’s departures from SFO on every route.
Weather source and limits. In full: SFO (airlines), SEA, What Weather Costs Each Airport, Who Cancels More When the Weather Turns, Airports That Change Places When Weather Turns.
Airlines on this route
Carriers with at least 200 flights, by the airline that operated each one.
| Carrier | Flights | On time | Cancelled | Median delay | Severe |
|---|---|---|---|---|---|
| Alaska Airlines | 8,621 | 71.6% | 1.74% | -1 min | 7.1% |
| United Airlines | 6,010 | 78.5% | 0.75% | -7 min | 6.5% |
| SkyWest Airlines | 3,386 | 74.5% | 0.50% | -4 min | 7.1% |
| Delta Air Lines | 2,747 | 85.4% | 1.02% | -16 min | 6.2% |
Alaska Airlines flew 41.5% of the 20,764 flights listed. Alaska Airlines cancelled 1.74% of its flights here against 0.50% for SkyWest Airlines.
Delta Air Lines arrived on time 13.8 percentage points more often than Alaska Airlines on this route.
Other ways to fly San Francisco to Seattle
Airport pairs in the same two city markets, as the DOT defines them.
| Route | Flights | On time | Cancelled | Median delay | Score |
|---|---|---|---|---|---|
| SFO→SEA this route San Francisco to Seattle | 20,767 | 75.9% | 1.16% | -5 min | 65 |
| SJC→SEA San Jose to Seattle | 13,899 | 83.9% | 0.80% | -8 min | 82 |
SJC → SEA is the most reliable pairing for this journey at 83.9% on time, against 75.9% for SFO → SEA.
Flying to SEA from the San Francisco area? Compare SFO, SJC, OAK for SEA, with the same test for what counts as a real difference.
Flights on this route
Flight numbers with at least 600 operations here and still on the schedule.
| Flight | Scheduled | Operations | On time |
|---|---|---|---|
| AS1327 Alaska Airlines | 7:55 PM | 672 | 57.6% |
Weekly and seasonal patterns
By day of week
Tuesday is historically the most reliable day and Friday the least, a gap of 8.5 percentage points.
By month
- Jan: 84.3%
- Feb: 81.3%
- Mar: 78.4%
- Apr: 75.2%
- May: 67.9%
- Jun: 64.4%
- Jul: 70.1%
- Aug: 75.4%
- Sep: 79.0%
- Oct: 81.5%
- Nov: 83.0%
- Dec: 77.0%
June is historically the weakest month and January the strongest, a spread of 19.9 percentage points.
Reliability over time
July 2023 – July 2026
- July 2023: 80.5% from 611 flights
- August 2023: 85.5% from 616 flights
- September 2023: 84.7% from 565 flights
- October 2023: 88.1% from 513 flights
- November 2023: 88.6% from 518 flights
- December 2023: 81.0% from 542 flights
- January 2024: 81.1% from 489 flights
- February 2024: 78.2% from 445 flights
- March 2024: 70.0% from 521 flights
- April 2024: 70.8% from 515 flights
- May 2024: 69.6% from 547 flights
- June 2024: 67.8% from 523 flights
- July 2024: 71.6% from 624 flights
- August 2024: 69.3% from 628 flights
- September 2024: 74.8% from 617 flights
- October 2024: 83.8% from 609 flights
- November 2024: 81.4% from 547 flights
- December 2024: 76.3% from 533 flights
- January 2025: 87.6% from 526 flights
- February 2025: 78.9% from 482 flights
- March 2025: 78.3% from 553 flights
- April 2025: 84.7% from 540 flights
- May 2025: 71.8% from 636 flights
- June 2025: 65.9% from 631 flights
- July 2025: 66.9% from 639 flights
- August 2025: 71.4% from 620 flights
- September 2025: 78.0% from 585 flights
- October 2025: 73.2% from 585 flights
- November 2025: 79.4% from 565 flights
- December 2025: 73.7% from 559 flights
- January 2026: 83.6% from 485 flights
- February 2026: 86.4% from 481 flights
- March 2026: 86.9% from 528 flights
- April 2026: 69.6% from 496 flights
- May 2026: 62.1% from 594 flights
- June 2026: 60.1% from 633 flights
- July 2026: 62.3% from 666 flights
Over the most recent 12 months (2025-08 to 2026-07), on-time arrivals averaged 73.2% against 76.2% in the 12 months before — declining by 3.0 percentage points.
Data and methodology
Calculated by FlyerIntel from 20,767 SFO → SEA flight records from the US DOT Bureau of Transportation Statistics, covering July 2023 – July 2026. Late means 15 or more minutes past scheduled arrival; cancelled and diverted flights are left out of on-time rates.
Full methodology · Data sources · Report a problem
Related research: How Long a Layover Needs to Be · Two Airlines on One Route · Best Time of Day to Fly From Major US Airports
Analysis last recomputed