OnTimeStats

Historical on-time performance

Seattle to San Francisco

679 miData through May 2026Source: US DOT · BTS

Flights on SEA–SFO arrive on time 68% of the time over the last 12 months.

On-time rate68%arrived within 15 min
p90 delay55 min1 in 10 flights is worse (tail risk)
Cancelled1.2%of scheduled flights

based on 6,757 flights over the last 12 months. On-time means arriving within 15 minutes (BTS standard).

By airline

How each carrier compares

  • SkyWest Airlinesbest
    On-time78%
    Medianon time
    p9035 min
    Cancel1.0%
    Flights1,108
  • United Airlines
    On-time71%
    Medianon time
    p9065 min
    Cancel0.7%
    Flights2,012
  • Delta Air Lines
    On-time68%
    Medianon time
    p9055 min
    Cancel1.8%
    Flights893
  • Alaska Airlines
    On-time61%
    Median5 min
    p9060 min
    Cancel1.4%
    Flights2,744

Why flights run late

Delay causes

  • Airline26%
  • Weather4%
  • Air traffic (NAS)48%
  • Late aircraft22%
  • Security0%

Most delay minutes here are attributed to Air traffic (NAS).

When flights don't go

Why flights were cancelled

  • Airline64%
  • Weather19%
  • Air traffic (NAS)18%
  • Security0%

Most cancellations here are attributed to Airline. Shares are among 80 cancellations with a reported cause (BTS reports causes from June 2003).

Over time

On-time trend

By season

On-time rate by month

When to fly

Best time to fly SEA → SFO

All airlines · rolling 36 months (2023-06 .. 2026-05).

Best time of day

On-time rates are fairly even by time of day on this route — ranging from 66% to 73% on time.

  • Afternoons73% on time · p90 50 min · 2,395 flights
  • Middays72% on time · p90 45 min · 4,742 flights
  • Mornings71% on time · p90 50 min · 6,407 flights
  • Overnights66% on time · p90 55 min · 2,110 flights
  • Evenings66% on time · p90 65 min · 4,427 flights

Best day of week

On-time rates are fairly even by day on this route — ranging from 66% to 77% on time.

  • Tuesdays77% on time · p90 35 min · 2,791 flights
  • Saturdays77% on time · p90 35 min · 2,489 flights
  • Wednesdays72% on time · p90 50 min · 2,810 flights
  • Thursdays67% on time · p90 55 min · 3,014 flights
  • Mondays67% on time · p90 55 min · 3,048 flights
  • Fridays66% on time · p90 60 min · 3,031 flights
  • Sundays66% on time · p90 60 min · 2,898 flights

Keep exploring

Related pages

Methodology

A flight is on time when it arrives within 15 minutes of schedule — the US DOT / BTS standard. Median and p90(the “1-in-10 bad day”) are read from the full arrival-delay distribution, never averaged across periods.

Figures cover a carrier’s own BTS-coded flights. Cells below ~200 flights are flagged as limited data. All numbers are pre-computed from public BTS On-Time Performance data.