Route profile
SEA→SFO
Flight reliability, delays and best times to fly from Seattle to San Francisco, 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 20% of comparable major US routes (4,598 compared)
Calculated from 20,772 flights. How this is calculated
SEA → SFO arrives on time 68.7% of the time; the return trip, SFO → SEA, arrives on time 75.9% of the time, a 7.2-point gap between the two directions of the same city pair.
SEA → SFO spends 31.2 minutes on the ground on a 679-mile trip: 24.6 minutes from pushback to wheels-up at SEA and 6.7 minutes from touchdown to gate at SFO.
Source: US DOT Bureau of Transportation Statistics · Data covering July 2023 – July 2026
What stands out
Reliability on this route has fallen unusually sharply over the past year, a bigger swing than 96% of 5,368 comparable routes.
62.2% on time over the most recent 12 months (2025-08 to 2026-07), against 74.6% in the 12 months before (2024-08 to 2025-07), a change of 12.4 points.
Source: FlyerIntel analysis of US DOT BTS data · July 2023 – July 2026 · Ranked against every other route with the same kind of figure and at least 5,368 in the comparison.
Why SEA → SFO flights are cancelled
July 2023 – July 2026
SEA → SFO cancelled 211 of 20,772 scheduled flights — about 1 in every 98. The reason filed most often was the airline, 77.3% of the cancellations coded on this route — about 1 in every 127 scheduled flights.
Share of cancellations
Of 211 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.
163 cancellations, 77.3% of the total.
Conditions the carrier judged severe enough to stop the flight: a blizzard, a hurricane, a line of thunderstorms.
28 cancellations, 13.3% of the total.
Airport capacity, air traffic control flow programs, heavy traffic and ordinary bad weather. A system decision, not the airline’s.
20 cancellations, 9.5% 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.
211 coded cancellations were recorded on SEA → SFO; the section appears from 50.
When it goes wrong
July 2023 – July 2026
57 min late
against a median of 0 min early
Percentiles over 20,772 operations; cancelled and diverted flights are counted separately.
Will your connection be tight enough?
Layovers at SFO after arriving from SEA.
| Connection time | Chance of missing | Reads as |
|---|---|---|
| 30 min | 50% | Likely to miss |
| 45 min | 30% | Likely to miss |
| 60 min | 20% | High risk |
| 90 min | 9.1% | Some risk |
| 120 min | 4.9% | 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 1.02% of the time and diverts 0.03% of the time, which a late arrival never shows up in.
Chance of missing is the share of 20,555 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 57 minutes late (90th-percentile gate arrival delay), over 20,772 operations.
Any other layover length: connection checker.
Best time to fly
SEA → SFO flights departing 12–3 PM arrived on time 74.5% of the time, against 58.8% for 6–9 PM departures, a gap of 15.7 percentage points.
By day and hour
On-time arrival rate for each weekday and scheduled departure hour, in local time at the departure airport (SEA).
Hour of departure matters more than day of the week: hourly averages sit a typical 8.4 points from the route-wide rate, weekday averages 4.4 points.
| Hour | Monday | Tuesday | Wednesday | Thursday | Friday | Saturday | Sunday |
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| 9 PM–10 PM |
On-time rate, % · stronger color, fewer on time
- 40–49
- 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 10 PM (701 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 | 81.1% on time151 flights | 87.8% on time158 flights | 89.7% on time148 flights | 87.6% on time146 flights | 82.1% on time151 flights | 91.4% on time151 flights | 87.2% on time142 flights |
| 7 AM–8 AM | 57.8% on time357 flights | 64.6% on time299 flights | 62.4% on time308 flights | 58.1% on time344 flights | 59.9% on time358 flights | 67.0% on time313 flights | 61.9% on time326 flights |
| 8 AM–9 AM | 50.7% on time139 flights | 62.8% on time149 flights | 60.5% on time150 flights | 57.9% on time148 flights | 56.2% on time138 flights | 66.9% on time156 flights | 61.0% on time120 flights |
| 9 AM–10 AM | 63.1% on time248 flights | 74.2% on time226 flights | 68.6% on time232 flights | 72.6% on time250 flights | 63.2% on time243 flights | 72.2% on time199 flights | 71.5% on time243 flights |
| 10 AM–11 AM | 80 flights, too few to score | 73 flights, too few to score | 72 flights, too few to score | 81 flights, too few to score | 79 flights, too few to score | 74 flights, too few to score | 89 flights, too few to score |
| 11 AM–12 PM | 60.8% on time205 flights | 73.3% on time195 flights | 67.2% on time198 flights | 68.3% on time202 flights | 60.4% on time199 flights | 76.7% on time165 flights | 67.2% on time181 flights |
| 12 PM–1 PM | 81 flights, too few to score | 85 flights, too few to score | 93 flights, too few to score | 82 flights, too few to score | 80 flights, too few to score | 80 flights, too few to score | 86 flights, too few to score |
| 1 PM–2 PM | 70.0% on time362 flights | 75.4% on time351 flights | 69.5% on time340 flights | 69.9% on time359 flights | 70.9% on time356 flights | 79.5% on time260 flights | 72.1% on time343 flights |
| 2 PM–3 PM | 100 flights, too few to score | 99 flights, too few to score | 98 flights, too few to score | 97 flights, too few to score | 99 flights, too few to score | 88 flights, too few to score | 92 flights, too few to score |
| 3 PM–4 PM | 68.5% on time181 flights | 85.4% on time185 flights | 76.9% on time195 flights | 64.4% on time180 flights | 65.0% on time180 flights | 72.8% on time152 flights | 68.0% on time155 flights |
| 4 PM–5 PM | 95 flights, too few to score | 82 flights, too few to score | 83 flights, too few to score | 84 flights, too few to score | 95 flights, too few to score | 80 flights, too few to score | 97 flights, too few to score |
| 5 PM–6 PM | 63.2% on time343 flights | 76.9% on time338 flights | 71.3% on time347 flights | 64.3% on time337 flights | 68.2% on time338 flights | 77.9% on time264 flights | 63.2% on time338 flights |
| 6 PM–7 PM | 82 flights, too few to score | 71 flights, too few to score | 69 flights, too few to score | 84 flights, too few to score | 88 flights, too few to score | 55 flights, too few to score | 100 flights, too few to score |
| 7 PM–8 PM | 52.8% on time285 flights | 72.7% on time250 flights | 63.4% on time257 flights | 53.6% on time276 flights | 50.7% on time274 flights | 64.7% on time203 flights | 49.4% on time245 flights |
| 8 PM–9 PM | 58.3% on time135 flights | 106 flights, too few to score | 114 flights, too few to score | 52.6% on time134 flights | 59.7% on time132 flights | 88 flights, too few to score | 48.6% on time142 flights |
| 9 PM–10 PM | 69.6% on time206 flights | 73.0% on time142 flights | 75.4% on time126 flights | 63.5% on time200 flights | 67.2% on time204 flights | 83.7% on time142 flights | 53.6% on time195 flights |
By departure window
By departure hour
- 12 AM to 4 AM: too few flights to score
- 5 AM: 93.8% on time from 625 flights
- 6 AM: 86.7% on time from 1,047 flights
- 7 AM: 61.5% on time from 2,305 flights
- 8 AM: 59.6% on time from 1,000 flights
- 9 AM: 69.2% on time from 1,641 flights
- 10 AM: 66.5% on time from 548 flights
- 11 AM: 67.4% on time from 1,345 flights
- 12 PM: 83.4% on time from 587 flights
- 1 PM: 72.2% on time from 2,371 flights
- 2 PM: 74.8% on time from 673 flights
- 3 PM: 71.8% on time from 1,228 flights
- 4 PM: 70.0% on time from 616 flights
- 5 PM: 69.0% on time from 2,305 flights
- 6 PM: 60.3% on time from 549 flights
- 7 PM: 57.8% on time from 1,790 flights
- 8 PM: 59.9% on time from 851 flights
- 9 PM: 68.3% on time from 1,215 flights
- 10 PM to 11 PM: too few flights to score
Why SEA → SFO runs late
July 2023 – July 2026
airspace and airport capacity, including weather-driven flow control
crew, maintenance, boarding and fueling, all within the carrier’s control
the inbound aircraft was late, so this flight started late
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 SEA → SFO. Only delays of 15 minutes or more are attributed.
How this route holds up in bad weather
July 2023 – July 2026
Bad weather raises cancellations by a similar amount at both ends of SEA to SFO: 1.9 times the normal rate at SEA and 1.7 times at SFO. Cancelled in bad weather against normal hours: SEA 1.5% against 0.8%, SFO 1.5% against 0.9%. 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 | SEA | SFO |
|---|---|---|
| Cancelled in bad weather | 1.5% | 1.5% |
| Cancelled in normal hours | 0.8% | 0.9% |
| Arrived on time, bad weather | 75.4% | 73.0% |
| Arrived on time, normal hours | 79.3% | 79.8% |
| Departures in bad weather | 43,416 | 36,006 |
Of the carriers on this route, United Airlines (0.8% cancelled against 1.5% for the other carriers at SEA) cancelled the fewest departures from SEA in bad weather and Alaska Airlines (1.8% cancelled against 1.2% for the other carriers at SEA) the most.
This route’s airlines in bad weather at SEA
All departures from SEA| Airline | Bad-weather departures | Cancelled | Other carriers |
|---|---|---|---|
| United Airlines | 2,531 | 0.8%below the others | 1.5% |
| Delta Air Lines | 9,020 | 1.1%below the others | 1.6% |
| SkyWest Airlines | 6,711 | 1.9%above the others | 1.5% |
| Alaska Airlines | 20,261 | 1.8%above the others | 1.2% |
These are airport figures, not route figures: every scheduled departure from SEA and SFO, to any destination, in hours the weather report called bad. The airline rows count each carrier’s departures from SEA on every route.
Weather source and limits. In full: SEA (airlines), SFO, 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 | 8,634 | 64.5% | 1.40% | 5 min | 9.1% |
| United Airlines | 6,012 | 71.5% | 0.80% | -4 min | 10.2% |
| SkyWest Airlines | 3,377 | 72.2% | 0.41% | -1 min | 8.1% |
| Delta Air Lines | 2,745 | 71.5% | 1.02% | -3 min | 9.1% |
Alaska Airlines flew 41.6% of the 20,768 flights listed.
SkyWest Airlines arrived on time 7.7 percentage points more often than Alaska Airlines on this route.
Other ways to fly Seattle to San Francisco
Airport pairs in the same two city markets, as the DOT defines them.
| Route | Flights | On time | Cancelled | Median delay | Score |
|---|---|---|---|---|---|
| SEA→SFO this route Seattle to San Francisco | 20,772 | 68.7% | 1.02% | 0 min | 53 |
| SEA→SJC Seattle to San Jose | 13,887 | 81.3% | 0.73% | -5 min | 78 |
SEA → SJC is the most reliable pairing for this journey at 81.3% on time, against 68.7% for SEA → SFO.
Flights on this route
Flight numbers with at least 600 operations here and still on the schedule.
| Flight | Scheduled | Operations | On time |
|---|---|---|---|
| UA737 United Airlines | 7:34 PM | 1,089 | 69.1% |
Weekly and seasonal patterns
By day of week
Saturday is historically the most reliable day and Sunday the least, a gap of 10.9 percentage points.
By month
- Jan: 78.8%
- Feb: 67.9%
- Mar: 69.5%
- Apr: 59.4%
- May: 58.2%
- Jun: 57.3%
- Jul: 63.2%
- Aug: 72.7%
- Sep: 74.9%
- Oct: 78.8%
- Nov: 76.6%
- Dec: 71.8%
June is historically the weakest month and January the strongest, a spread of 21.5 percentage points.
Reliability over time
July 2023 – July 2026
- July 2023: 74.5% from 611 flights
- August 2023: 79.1% from 616 flights
- September 2023: 77.6% from 566 flights
- October 2023: 83.3% from 515 flights
- November 2023: 80.7% from 517 flights
- December 2023: 76.7% from 546 flights
- January 2024: 71.9% from 487 flights
- February 2024: 57.5% from 445 flights
- March 2024: 53.2% from 523 flights
- April 2024: 50.0% from 517 flights
- May 2024: 55.0% from 545 flights
- June 2024: 61.7% from 523 flights
- July 2024: 74.9% from 624 flights
- August 2024: 65.0% from 627 flights
- September 2024: 72.2% from 617 flights
- October 2024: 80.4% from 611 flights
- November 2024: 77.1% from 548 flights
- December 2024: 72.6% from 532 flights
- January 2025: 87.1% from 523 flights
- February 2025: 71.0% from 484 flights
- March 2025: 73.4% from 560 flights
- April 2025: 78.4% from 539 flights
- May 2025: 76.9% from 636 flights
- June 2025: 71.9% from 630 flights
- July 2025: 70.7% from 639 flights
- August 2025: 73.9% from 619 flights
- September 2025: 75.2% from 584 flights
- October 2025: 73.0% from 584 flights
- November 2025: 72.2% from 567 flights
- December 2025: 66.1% from 558 flights
- January 2026: 76.3% from 486 flights
- February 2026: 74.3% from 480 flights
- March 2026: 81.7% from 528 flights
- April 2026: 48.5% from 495 flights
- May 2026: 40.7% from 591 flights
- June 2026: 39.2% from 633 flights
- July 2026: 35.0% from 666 flights
Over the most recent 12 months (2025-08 to 2026-07), on-time arrivals averaged 62.2% against 74.6% in the 12 months before — declining by 12.4 percentage points.
Data and methodology
Calculated by FlyerIntel from 20,772 SEA → SFO 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