SEA to SFO flight delays
Seattle, WA (SEA) San Francisco, CA (SFO) · 679 miles
633 flights · March 2025 – August 2026 · US Bureau of Transportation Statistics
39.17%
Arrived on time
Within 15 minutes of schedule
0.79%
Cancelled
Share of scheduled flights
55 min
When late, late by
Average across delayed arrivals
35 min
Delay per flight
Averaged over every flight flown
What the record says about this route
Which airline you fly changes the odds here. Alaska Airlines arrived on time 7.8 points more often than United Airlines over the same period on the same route — same airports, same weather, same air traffic control. A gap that survives all of that is about how the two airlines are run.
Flights from Seattle to San Francisco arrive late more often than they arrive on time. At this rate lateness is the normal outcome, not the exception, and the schedule is better read as an aspiration than a plan.
The two directions do not behave alike. SFO to SEA arrives on time 20.9 points more often than the outbound. Delay accumulates through the flying day, so whichever direction is scheduled later tends to carry the worse record — which is an argument for booking the morning departure if the choice exists.
This route does worse than its own airport. SEA as a whole runs 35.2 points more punctual than these flights, which points at something specific to the route — the time of day it is scheduled, or the aircraft that feed it — rather than the airport.
Which airline should you fly on this route?
Over March 2025 – August 2026, Alaska Airlines arrived on time most often on SEA to SFO. United Airlines was late most often.
Every airline on SEA to SFO
Ranked by how many flights each one operated. A carrier with fewer than 100 flights in the period is listed but not graded.
| Airline | Flights | On time | Cancelled | Avg delay | Grade |
|---|---|---|---|---|---|
| Alaska Airlines | 252 | 37.35% | 1.19% | 51 min | F |
| United Airlines | 195 | 29.53% | 1.03% | 64 min | F |
| SkyWest Airlines | 96 | 48.96% | 0% | 52 min | — |
| Delta Air Lines | 90 | 54.44% | 0% | 45 min | — |
The return leg
SFO to SEA San Francisco back to Seattle 60.1% on time FOther routes from Seattle
Common questions
Are flights from Seattle to San Francisco usually delayed?
39.17% of flights on the SEA to SFO route arrived within 15 minutes of schedule, so roughly 6 in every ten arrived late. That is worse than the average route in this record.
Which airline is most on time from Seattle to San Francisco?
Alaska Airlines, at 37.35% on time across 252 flights. The least punctual on the route was United Airlines at 29.53%.
How often are SEA to SFO flights cancelled?
0.79% of scheduled flights did not operate — about 8 in every thousand. That is in the normal range.
When SEA to SFO flights are late, how late are they?
About 55 minutes on average across the flights that arrived more than 15 minutes behind schedule.
What these figures do and do not tell you
Everything on this page is counted from the flights that actually operated on SEA to SFO during March 2025 – August 2026, as reported by the airlines to the US Bureau of Transportation Statistics. "On time" is the federal definition: arriving at the gate within 15 minutes of the scheduled time.
A route's record is a description of the past, not a forecast. Weather, air traffic control and the aircraft's earlier flights that day drive most delays, and none of them are predictable from a historical rate. What the record does tell you is whether this route runs late more often than others, and which carrier on it has the better history — which is the part you can actually act on when you book.
Cancellations are counted separately from delays because they are a different problem for a traveller: a late flight still gets you there. How the grade is calculated →