Seattle to San Francisco Flight Delays
Sample size: 19,967 SEA–SFO flights, January 2023 to December 2025 (BTS). 27.58% of Seattle to San Francisco flights arrived at least 15 minutes late. That is 3.4 points worse than the 24.2% median for those routes, so schedule padding matters here. Departure time moves the odds more than anything else on this route: 05:00 departures run 5.19% late against 36.92% for 19:00. Saturday is the calmest day at 21.57%, Sunday the worst at 32.06%. Cancellations (2024 to 2025) peak in January at 3.37% of scheduled flights and bottom out in March at 0.28%. Last updated: 2026-10-01.
SEA airport delay guide · SFO airport delay guide · Predict a SEA to SFO flight
Best time to fly SEA to SFO
The best time to fly SEA to SFO is the 5 AM departure and fly on a Saturday, not a Sunday (21.57% against 32.06%): 5.19% of 5 AM flights arrived 15+ minutes late, against 36.92% at 7 PM.
Lowest observed delay rates depart 05:00–06:00, 12:00. The highest sit at 18:00–20:00. Only departure hours with at least 100 recorded flights are listed, so sparse hours are blank rather than estimated.
SEA to SFO delay rate by scheduled departure hour, January 2023 to December 2025
| Departure hour | Delayed 15+ min | Flights observed |
|---|
| 05:00 | 5.19% | 655 |
| 06:00 | 12.16% | 1,135 |
| 07:00 | 33.83% | 2,205 |
| 08:00 | 33.38% | 704 |
| 09:00 | 29.12% | 1,861 |
| 10:00 | 25.19% | 532 |
| 11:00 | 32.94% | 1,108 |
| 12:00 | 16.79% | 542 |
| 13:00 | 24.59% | 2,338 |
| 14:00 | 18.95% | 649 |
| 15:00 | 26.16% | 1,189 |
| 16:00 | 28.78% | 556 |
| 17:00 | 26.19% | 2,100 |
| 18:00 | 34.17% | 480 |
| 19:00 | 36.92% | 1,785 |
| 20:00 | 34.52% | 872 |
| 21:00 | 30.01% | 1,183 |
SEA to SFO flight time and distance
Scheduled gate-to-gate time from SEA to SFO is a median 2 h 14 min. Flights actually took a median 2 h 10 min gate to gate, including 1 h 41 min in the air. 2.5% ran 30 or more minutes over schedule and 61.9% arrived sooner than scheduled (BTS data, January 2023 to December 2025).
SEA to SFO is 679 miles (BTS data).
SEA to SFO flight time by airline, January 2023 to December 2025
| Airline | Scheduled (median) | Actual (median) | In the air (median) | 30+ min over schedule | Flights |
|---|
| Alaska Airlines | 2 h 13 min | 2 h 10 min | 1 h 41 min | 2.2% | 8,592 |
| United Airlines | 2 h 16 min | 2 h 8 min | 1 h 41 min | 2.6% | 5,547 |
| SkyWest Airlines | 2 h 19 min | 2 h 15 min | 1 h 45 min | 3.9% | 3,177 |
| Delta Air Lines | 2 h 14 min | 2 h 9 min | 1 h 40 min | 1.9% | 2,651 |
How late, and why
When a SEA to SFO flight was late (15+ minutes), it arrived an average of 57 minutes late (median 39). 8.1% of all completed flights arrived an hour or more late (BTS data, 2023 to 2025).
Of the delay minutes on late SEA to SFO flights, 43.6% were caused by the air-traffic system (volume, non-extreme weather, airport operations), 29.5% by the airline (crew, maintenance, ground handling), 21.5% by a late incoming aircraft, 5.3% by extreme weather and 0.1% by security (BTS data, 2023 to 2025).
Causes of delay minutes on late SEA to SFO flights
| Cause | Share of delay minutes |
|---|
| air-traffic system | 43.6% |
| airline | 29.5% |
| late incoming aircraft | 21.5% |
| extreme weather | 5.3% |
| security | 0.1% |
BTS assigns causes to delay minutes on flights that arrived 15+ minutes late. "Air-traffic system" includes non-extreme weather that slows traffic.
SEA to SFO delays by day of week
Seattle to San Francisco delay rate by day of week, January 2023 to December 2025
| Day | Delayed 15+ min | Flights observed |
|---|
| Mon | 30.13% | 3,050 |
| Tue | 21.94% | 2,835 |
| Wed | 25.34% | 2,834 |
| Thu | 29.89% | 2,981 |
| Fri | 30.75% | 3,002 |
| Sat | 21.57% | 2,420 |
| Sun | 32.06% | 2,845 |
Month-by-month cancellation pattern
Share of scheduled SEA–SFO flights cancelled in each month, from BTS 2024–2025 on-time reporting. These are cancellations, not delays. Delay figures on this page cover January 2023 to December 2025.
Seattle to San Francisco monthly cancellation rate
| Month | Cancelled | Flights scheduled |
|---|
| Jan | 3.37% | 1,010 |
| Feb | 1.61% | 929 |
| Mar | 0.28% | 1,083 |
| Apr | 0.28% | 1,056 |
| May | 0.51% | 1,181 |
| Jun | 0.61% | 1,153 |
| Jul | 2.38% | 1,263 |
| Aug | 0.96% | 1,246 |
| Sep | 0.75% | 1,201 |
| Oct | 0.84% | 1,195 |
| Nov | 1.7% | 1,115 |
| Dec | 0.55% | 1,090 |
Airlines on SEA to SFO: delays and cancellations
Alaska Airlines, United Airlines, SkyWest Airlines and Delta Air Lines fly this route today. Only carriers with at least 200 scheduled flights on the pairing are listed. Delay rates cover January 2023 to December 2025; cancellation rates cover 2024 to 2025.
Carriers on Seattle to San Francisco
| Airline | Share of flights | Delayed 15+ min | Cancelled | Flights scheduled |
|---|
| Alaska Airlines | 41% | 31.82% | 1.83% | 5,575 |
| United Airlines | 29% | 23.51% | 0.79% | 3,930 |
| SkyWest Airlines | 19% | 24.71% | 0.4% | 2,525 |
| Delta Air Lines | 11% | 25.8% | 0.74% | 1,492 |
SEA vs SFO: airport conditions
Both ends of a route shape its delay profile. These are DelayGuard's operational scores for Seattle and San Francisco.
Airport comparison, SEA against SFO
| Measure | SEA (Seattle) | SFO (San Francisco) |
|---|
| Congestion | high | high |
| Weather risk | moderate | moderate |
| NAS vulnerability | moderate | high |
| Average taxi-out | 14 min | 15 min |
| Runways | 3 | 4 |
SEA to SFO questions
- How long is the flight from Seattle to San Francisco?
- Scheduled gate-to-gate time from SEA to SFO is a median 2 h 14 min, and flights actually took a median 2 h 10 min including 1 h 41 min in the air. 2.5% ran 30+ minutes over schedule (BTS data, January 2023 to December 2025).
- How often do SEA to SFO flights get delayed?
- Across 19,967 recorded SEA–SFO departures, January 2023 to December 2025 (BTS), 27.58% arrived at least 15 minutes late. Departure time matters most: 5:00 departures run 5.19% late against 36.92% for 19:00. Actual delay frequency varies by airline, time of day, and season.
- What is the best time of year to fly SEA to SFO?
- Both Seattle and San Francisco share the same primary risk window: November–February (coastal fog) with generally low risk year-round. Plan around those periods for the lowest delay probability on this route.
- Which airline is most reliable on SEA to SFO?
- On SEA→SFO, United Airlines has the lowest measured delay rate at 23.51% of 5,547 flights, and Alaska Airlines the highest at 31.82% (BTS, January 2023 to December 2025). SkyWest Airlines cancels the fewest at 0.4% (2024 to 2025). These are route-specific figures, not airline-wide averages.
- How late are SEA to SFO flights when they are delayed?
- When a SEA to SFO flight was late (15+ minutes), it arrived an average of 57 minutes late (median 39). 8.1% of all completed flights arrived an hour or more late (BTS data, 2023 to 2025).
- How accurate is DelayGuard's delay prediction for this route?
- DelayGuard's delay risk score comes from an ML model trained on BTS data (3.95 million US domestic flights, 2023 to mid-2025), with live weather data (within 5 days of departure) and FAA NAS advisories (within 6 hours) — a likelihood of delay, not a guarantee.
Delay figures reflect arrivals 15 or more minutes late in BTS on-time reporting. Cancellation figures are separate and count flights that never operated. Hours, days and months with fewer than 100 recorded flights are omitted rather than estimated.