San Francisco to Seattle Flight Delays
Sample size: 19,926 SFO–SEA flights, January 2023 to December 2025 (BTS). 22.56% of San Francisco to Seattle flights arrived at least 15 minutes late. That is 1.6 points better than the 24.2% median for those routes, making this one of the steadier pairings in the network. Departure time moves the odds more than anything else on this route: 05:00 departures run 3.76% late against 35.44% for 19:00. Tuesday is the calmest day at 18.13%, Sunday the worst at 26.3%. Cancellations (2024 to 2025) peak in January at 5.02% of scheduled flights and bottom out in March at 0.47%. Last updated: 2026-10-01.
These figures are historical US domestic rates, not a forecast for one departure. Use the US domestic delay forecast before you book.
SFO airport delay guide · SEA airport delay guide · Predict a SFO to SEA flight
Best time to fly SFO to SEA
The best time to fly SFO to SEA is the 5 AM departure and fly on a Tuesday, not a Sunday (18.13% against 26.3%): 3.76% of 5 AM flights arrived 15+ minutes late, against 35.44% at 7 PM.
Lowest observed delay rates depart 05:00–07:00. The highest sit at 08:00, 15:00, 19:00. Only departure hours with at least 100 recorded flights are listed, so sparse hours are blank rather than estimated.
| Departure hour | Delayed 15+ min | Flights observed |
|---|---|---|
| 05:00 | 3.76% | 319 |
| 06:00 | 6.4% | 1,813 |
| 07:00 | 10.68% | 646 |
| 08:00 | 30.59% | 935 |
| 09:00 | 17% | 1,359 |
| 10:00 | 21.98% | 1,629 |
| 11:00 | 23.46% | 874 |
| 12:00 | 25.46% | 1,316 |
| 13:00 | 17.75% | 1,251 |
| 14:00 | 30.02% | 1,046 |
| 15:00 | 31.21% | 173 |
| 16:00 | 24.59% | 2,757 |
| 17:00 | 17.73% | 660 |
| 18:00 | 28.6% | 972 |
| 19:00 | 35.44% | 1,473 |
| 20:00 | 26.26% | 1,291 |
| 21:00 | 24.17% | 753 |
| 22:00 | 25.2% | 631 |
SFO to SEA flight time and distance
Scheduled gate-to-gate time from SFO to SEA is a median 2 h 16 min. Flights actually took a median 2 h 8 min gate to gate, including 1 h 37 min in the air. 2.2% ran 30 or more minutes over schedule and 71.7% arrived sooner than scheduled (BTS data, January 2023 to December 2025).
SFO to SEA is 679 miles (BTS data).
| Airline | Scheduled (median) | Actual (median) | In the air (median) | 30+ min over schedule | Flights |
|---|---|---|---|---|---|
| Alaska Airlines | 2 h 15 min | 2 h 9 min | 1 h 37 min | 3.6% | 8,546 |
| United Airlines | 2 h 18 min | 2 h 8 min | 1 h 36 min | 1.3% | 5,546 |
| SkyWest Airlines | 2 h 18 min | 2 h 11 min | 1 h 40 min | 1.5% | 3,181 |
| Delta Air Lines | 2 h 19 min | 2 h 4 min | 1 h 36 min | 0.2% | 2,653 |
How late, and why
When a SFO to SEA flight was late (15+ minutes), it arrived an average of 58 minutes late (median 36). 6.4% of all completed flights arrived an hour or more late (BTS data, 2023 to 2025).
Of the delay minutes on late SFO to SEA flights, 46.4% were caused by a late incoming aircraft, 27.9% by the airline (crew, maintenance, ground handling), 21.5% by the air-traffic system (volume, non-extreme weather, airport operations), 4.1% by extreme weather and 0.1% by security (BTS data, 2023 to 2025).
| Cause | Share of delay minutes |
|---|---|
| late incoming aircraft | 46.4% |
| airline | 27.9% |
| air-traffic system | 21.5% |
| extreme weather | 4.1% |
| 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.
SFO to SEA delays by day of week
| Day | Delayed 15+ min | Flights observed |
|---|---|---|
| Mon | 24.53% | 3,045 |
| Tue | 18.13% | 2,840 |
| Wed | 20.52% | 2,836 |
| Thu | 22.81% | 2,973 |
| Fri | 25.46% | 2,961 |
| Sat | 19.32% | 2,397 |
| Sun | 26.3% | 2,874 |
Month-by-month cancellation pattern
Share of scheduled SFO–SEA 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.
| Month | Cancelled | Flights scheduled |
|---|---|---|
| Jan | 5.02% | 1,015 |
| Feb | 1.51% | 927 |
| Mar | 0.47% | 1,074 |
| Apr | 0.47% | 1,055 |
| May | 0.51% | 1,183 |
| Jun | 0.52% | 1,154 |
| Jul | 2.22% | 1,263 |
| Aug | 1.28% | 1,248 |
| Sep | 0.67% | 1,202 |
| Oct | 0.92% | 1,194 |
| Nov | 1.89% | 1,112 |
| Dec | 0.55% | 1,092 |
Airlines on SFO to SEA: 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.
| Airline | Share of flights | Delayed 15+ min | Cancelled | Flights scheduled |
|---|---|---|---|---|
| Alaska Airlines | 41% | 26.68% | 2.21% | 5,567 |
| United Airlines | 29% | 20.63% | 0.84% | 3,927 |
| SkyWest Airlines | 19% | 21.94% | 0.43% | 2,532 |
| Delta Air Lines | 11% | 14.06% | 0.67% | 1,493 |
Related pages
- SFO delays: rate, worst hours and live risk
- SEA delays: rate, worst hours and live risk
- US airline cancellation rates
- Thanksgiving and Christmas 2026 flight delay guide
- Predict a SFO to SEA flight
Check your odds: Will my flight be delayed? · Will my flight be cancelled?
SFO vs SEA: airport conditions
Both ends of a route shape its delay profile. These are DelayGuard's operational scores for San Francisco and Seattle.
| Measure | SFO (San Francisco) | SEA (Seattle) |
|---|---|---|
| Congestion | high | high |
| Weather risk | moderate | moderate |
| NAS vulnerability | high | moderate |
| Average taxi-out | 15 min | 14 min |
| Runways | 4 | 3 |
SFO to SEA questions
- How long is the flight from San Francisco to Seattle?
- Scheduled gate-to-gate time from SFO to SEA is a median 2 h 16 min, and flights actually took a median 2 h 8 min including 1 h 37 min in the air. 2.2% ran 30+ minutes over schedule (BTS data, January 2023 to December 2025).
- How often do SFO to SEA flights get delayed?
- Across 19,926 recorded SFO–SEA departures, January 2023 to December 2025 (BTS), 22.56% arrived at least 15 minutes late. Departure time matters most: 5:00 departures run 3.76% late against 35.44% for 19:00. Actual delay frequency varies by airline, time of day, and season.
- What is the best time of year to fly SFO to SEA?
- Both San Francisco and Seattle 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 SFO to SEA?
- On SFO→SEA, Delta Air Lines has the lowest measured delay rate at 14.06% of 2,653 flights, and Alaska Airlines the highest at 26.68% (BTS, January 2023 to December 2025). SkyWest Airlines cancels the fewest at 0.43% (2024 to 2025). These are route-specific figures, not airline-wide averages.
- How late are SFO to SEA flights when they are delayed?
- When a SFO to SEA flight was late (15+ minutes), it arrived an average of 58 minutes late (median 36). 6.4% 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.