OnTimeStats

Historical on-time performance

San Antonio to Chicago

1,036 miData through Dec 2025Source: US DOT · BTS

Flights on SAT–MDW arrive on time 85% of the time over the last 12 months.

On-time rate85%arrived within 15 min
p90 delay20 min1 in 10 flights is worse (tail risk)
Cancelled0.8%of scheduled flights

based on 734 flights over the last 12 months. On-time means arriving within 15 minutes (BTS standard).

By airline

How each carrier compares

  • Southwest Airlines
    On-time85%
    Medianon time
    p9020 min
    Cancel0.8%
    Flights734

Why flights run late

Delay causes

  • Airline26%
  • Weather3%
  • Air traffic (NAS)19%
  • Late aircraft52%
  • Security0%

Most delay minutes here are attributed to Late aircraft.

Over time

On-time trend

By season

On-time rate by month

When to fly

Best time to fly SAT → MDW

All airlines · rolling 36 months (2023-01 .. 2025-12).

Best time of day

On-time rates are fairly even by time of day on this route — ranging from 78% to 92% on time.

  • Mornings92% on time · p90 10 min · 1,026 flights
  • Middays89% on time · p90 15 min · 130 flights · limited
  • Evenings79% on time · p90 40 min · 100 flights · limited
  • Afternoons78% on time · p90 30 min · 874 flights

Best day of week

On-time rates are fairly even by day on this route — ranging from 81% to 90% on time.

  • Saturdays90% on time · p90 10 min · 250 flights
  • Tuesdays89% on time · p90 15 min · 314 flights
  • Mondays86% on time · p90 15 min · 323 flights
  • Wednesdays86% on time · p90 15 min · 314 flights
  • Sundays84% on time · p90 20 min · 291 flights
  • Fridays84% on time · p90 20 min · 320 flights
  • Thursdays81% on time · p90 25 min · 318 flights
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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.