OnTimeStats

Historical on-time performance

Chicago to San Francisco

1,855 miData through May 2026Source: US DOT · BTS

Flights on MDW–SFO arrive on time 50% of the time over the last 12 months.

On-time rate50%arrived within 15 min
p90 delay65 min1 in 10 flights is worse (tail risk)
Cancelled1.5%of scheduled flights

based on 392 flights over the last 12 months. On-time means arriving within 15 minutes (BTS standard).

By airline

How each carrier compares

  • Southwest Airlines
    On-time50%
    Median10 min
    p9065 min
    Cancel1.5%
    Flights392

Why flights run late

Delay causes

  • Airline26%
  • Weather3%
  • Air traffic (NAS)39%
  • Late aircraft33%
  • Security0%

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

When flights don't go

Why flights were cancelled

  • Airline0%
  • Weather83%
  • Air traffic (NAS)17%
  • Security0%

Most cancellations here are attributed to Weather. Shares are among 6 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 MDW → SFO

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

Best time of day

Mornings are the most reliable time of day to fly this route — 74% on time.

  • Mornings74% on time · p90 45 min · 270 flights
  • Evenings60% on time · p90 70 min · 130 flights · limited
  • Afternoons54% on time · p90 110 min · 228 flights
  • Middays54% on time · p90 60 min · 357 flights
  • Overnights39% on time · p90 85 min · 170 flights · limited

Best day of week

On-time rates are fairly even by day on this route — ranging from 51% to 62% on time.

  • Tuesdays62% on time · p90 75 min · 145 flights · limited
  • Saturdays61% on time · p90 65 min · 174 flights · limited
  • Sundays60% on time · p90 65 min · 153 flights · limited
  • Mondays59% on time · p90 60 min · 179 flights · limited
  • Thursdays55% on time · p90 75 min · 166 flights · limited
  • Wednesdays53% on time · p90 65 min · 156 flights · limited
  • Fridays51% on time · p90 75 min · 182 flights · limited

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.