OnTimeStats

Historical on-time performance

Chicago to Decatur

156 miData through May 2026Source: US DOT · BTS

Flights on ORD–DEC arrive on time 67% of the time over the last 12 months.

On-time rate67%arrived within 15 min
p90 delay85 min1 in 10 flights is worse (tail risk)
Cancelled3.7%of scheduled flights

based on 627 flights over the last 12 months. On-time means arriving within 15 minutes (BTS standard).

By airline

How each carrier compares

  • SkyWest Airlines
    On-time67%
    Medianon time
    p9085 min
    Cancel3.7%
    Flights627

Why flights run late

Delay causes

  • Airline32%
  • Weather5%
  • Air traffic (NAS)23%
  • Late aircraft39%
  • Security0%

Most delay minutes here are attributed to Late aircraft.

When flights don't go

Why flights were cancelled

  • Airline0%
  • Weather87%
  • Air traffic (NAS)13%
  • Security0%

Most cancellations here are attributed to Weather. Shares are among 23 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 ORD → DEC

All airlines · rolling 36 months (2023-06 .. 2026-05).

Best time of day

On-time rates are fairly even by time of day on this route — ranging from 68% to 79% on time.

  • Middays79% on time · p90 55 min · 414 flights
  • Mornings77% on time · p90 40 min · 604 flights
  • Afternoons68% on time · p90 90 min · 820 flights

Best day of week

On-time rates are fairly even by day on this route — ranging from 69% to 74% on time.

  • Thursdays74% on time · p90 60 min · 309 flights
  • Fridays74% on time · p90 60 min · 314 flights
  • Mondays74% on time · p90 50 min · 310 flights
  • Wednesdays74% on time · p90 70 min · 310 flights
  • Tuesdays73% on time · p90 90 min · 160 flights · limited
  • Saturdays73% on time · p90 75 min · 161 flights · limited
  • Sundays69% on time · p90 70 min · 313 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.