OnTimeStats

Historical on-time performance

St. Louis to Chicago

258 miData through May 2026Source: US DOT · BTS

Flights on STL–ORD arrive on time 69% of the time over the last 12 months.

On-time rate69%arrived within 15 min
p90 delay75 min1 in 10 flights is worse (tail risk)
Cancelled2.9%of scheduled flights

based on 2,753 flights over the last 12 months. On-time means arriving within 15 minutes (BTS standard).

By airline

How each carrier compares

  • American Airlinesbest
    On-time80%
    Medianon time
    p9045 min
    Cancel1.8%
    Flights542
  • Envoy Air
    On-time73%
    Medianon time
    p9050 min
    Cancel2.3%
    Flights646
  • Republic Airways
    On-time67%
    Medianon time
    p9090 min
    Cancel3.7%
    Flights326
  • United Airlines
    On-time67%
    Medianon time
    p9055 min
    Cancel1.0%
    Flights399
  • SkyWest Airlines
    On-time60%
    Medianon time
    p9095 min
    Cancel4.6%
    Flights840

Why flights run late

Delay causes

  • Airline31%
  • Weather8%
  • Air traffic (NAS)30%
  • Late aircraft31%
  • Security0%

Most delay minutes here are attributed to Airline.

When flights don't go

Why flights were cancelled

  • Airline3%
  • Weather79%
  • Air traffic (NAS)19%
  • Security0%

Most cancellations here are attributed to Weather. Shares are among 80 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 STL → ORD

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 — 83% on time.

  • Mornings83% on time · p90 30 min · 2,492 flights
  • Middays80% on time · p90 40 min · 1,932 flights
  • Afternoons72% on time · p90 65 min · 1,625 flights
  • Evenings61% on time · p90 80 min · 1,917 flights
  • Overnights49% on time · p90 115 min · 156 flights · limited

Best day of week

On-time rates are fairly even by day on this route — ranging from 71% to 78% on time.

  • Saturdays78% on time · p90 45 min · 1,043 flights
  • Tuesdays76% on time · p90 55 min · 1,134 flights
  • Wednesdays75% on time · p90 50 min · 1,153 flights
  • Thursdays75% on time · p90 55 min · 1,198 flights
  • Mondays73% on time · p90 60 min · 1,196 flights
  • Sundays72% on time · p90 60 min · 1,182 flights
  • Fridays71% on time · p90 60 min · 1,216 flights

Keep exploring

Related pages

Delay predictorfor this route→STL airportSt. Louis→ORD airportChicago→SkyWest Airlinesairline profile→Envoy Airairline profile→American Airlinesairline profile→Seasonal delay patternsguide→

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.