OnTimeStats

Historical on-time performance

Louisville to Chicago

271 miData through May 2026Source: US DOT · BTS

Flights on SDF–MDW arrive on time 84% of the time over the last 12 months.

On-time rate84%arrived within 15 min
p90 delay30 min1 in 10 flights is worse (tail risk)
Cancelled1.6%of scheduled flights

based on 1,001 flights over the last 12 months. On-time means arriving within 15 minutes (BTS standard).

By airline

How each carrier compares

  • Southwest Airlines
    On-time84%
    Medianon time
    p9030 min
    Cancel1.6%
    Flights1,001

Why flights run late

Delay causes

  • Airline21%
  • Weather1%
  • Air traffic (NAS)22%
  • Late aircraft57%
  • Security0%

Most delay minutes here are attributed to Late aircraft.

When flights don't go

Why flights were cancelled

  • Airline13%
  • Weather75%
  • Air traffic (NAS)13%
  • Security0%

Most cancellations here are attributed to Weather. Shares are among 16 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 SDF → MDW

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 — 91% on time.

  • Mornings91% on time · p90 5 min · 1,091 flights
  • Middays87% on time · p90 20 min · 457 flights
  • Afternoons83% on time · p90 30 min · 483 flights
  • Evenings80% on time · p90 30 min · 604 flights
  • Overnights74% on time · p90 70 min · 434 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 5 min · 326 flights
  • Tuesdays89% on time · p90 15 min · 451 flights
  • Wednesdays87% on time · p90 15 min · 452 flights
  • Fridays84% on time · p90 25 min · 466 flights
  • Thursdays83% on time · p90 30 min · 469 flights
  • Sundays82% on time · p90 35 min · 441 flights
  • Mondays81% on time · p90 30 min · 464 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.