OnTimeStats

Historical on-time performance

Los Angeles to Chicago

1,751 miData through Dec 2025Source: US DOT · BTS

Flights on LAX–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)
Cancelled0.4%of scheduled flights

based on 1,367 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
    Cancel0.4%
    Flights1,367

Why flights run late

Delay causes

  • Airline31%
  • Weather1%
  • Air traffic (NAS)12%
  • Late aircraft56%
  • 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 LAX → MDW

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

Best time of day

Mornings are the most reliable time of day to fly this route — 92% on time.

  • Mornings92% on time · p90 10 min · 1,452 flights
  • Overnights87% on time · p90 15 min · 316 flights
  • Middays80% on time · p90 25 min · 1,083 flights
  • Evenings69% on time · p90 50 min · 771 flights
  • Afternoons61% on time · p90 60 min · 552 flights

Best day of week

Saturdays are the most reliable day to fly this route — 87% on time.

  • Saturdays87% on time · p90 15 min · 474 flights
  • Wednesdays82% on time · p90 25 min · 605 flights
  • Tuesdays81% on time · p90 30 min · 609 flights
  • Mondays80% on time · p90 35 min · 647 flights
  • Thursdays79% on time · p90 35 min · 635 flights
  • Sundays77% on time · p90 30 min · 558 flights
  • Fridays77% on time · p90 30 min · 646 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.