OnTimeStats

Historical on-time performance

Chicago to St. Louis

251 miData through May 2026Source: US DOT · BTS

Flights on MDW–STL arrive on time 81% of the time over the last 12 months.

On-time rate81%arrived within 15 min
p90 delay30 min1 in 10 flights is worse (tail risk)
Cancelled0.9%of scheduled flights

based on 1,705 flights over the last 12 months. On-time means arriving within 15 minutes (BTS standard).

By airline

How each carrier compares

  • Southwest Airlines
    On-time81%
    Medianon time
    p9030 min
    Cancel0.9%
    Flights1,705

Why flights run late

Delay causes

  • Airline34%
  • Weather1%
  • Air traffic (NAS)11%
  • Late aircraft54%
  • Security0%

Most delay minutes here are attributed to Late aircraft.

When flights don't go

Why flights were cancelled

  • Airline31%
  • Weather63%
  • Air traffic (NAS)6%
  • 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 MDW → STL

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 — 93% on time.

  • Mornings93% on time · p90 5 min · 1,878 flights
  • Middays87% on time · p90 15 min · 1,146 flights
  • Afternoons76% on time · p90 40 min · 606 flights
  • Evenings72% on time · p90 50 min · 994 flights
  • Overnights65% on time · p90 60 min · 1,035 flights

Best day of week

On-time rates are fairly even by day on this route — ranging from 75% to 85% on time.

  • Tuesdays85% on time · p90 25 min · 851 flights
  • Wednesdays84% on time · p90 25 min · 849 flights
  • Saturdays82% on time · p90 25 min · 536 flights
  • Thursdays82% on time · p90 30 min · 871 flights
  • Fridays81% on time · p90 30 min · 871 flights
  • Mondays81% on time · p90 30 min · 872 flights
  • Sundays75% on time · p90 45 min · 809 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.