OnTimeStats

Historical on-time performance

Chicago to Missoula

1,332 miData through Dec 2025Source: US DOT · BTS

Flights on ORD–MSO arrive on time 79% of the time over the last 12 months.

On-time rate79%arrived within 15 min
p90 delay40 min1 in 10 flights is worse (tail risk)
Cancelled0.3%of scheduled flights

based on 312 flights over the last 12 months. On-time means arriving within 15 minutes (BTS standard).

By airline

How each carrier compares

  • Envoy Air
    On-time75%
    Medianon time
    p9045 min
    Cancel0.5%
    Flights220
  • United Airlinesbest
    On-time87%
    Medianon time
    p9020 min
    Cancel0.0%
    Flights92

Why flights run late

Delay causes

  • Airline28%
  • Weather24%
  • Air traffic (NAS)20%
  • Late aircraft28%
  • 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 ORD → MSO

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

Best time of day

On-time rates are fairly even by time of day on this route — ranging from 66% to 81% on time.

  • Mornings81% on time · p90 30 min · 668 flights
  • Middays79% on time · p90 50 min · 53 flights · limited
  • Overnights66% on time · p90 75 min · 108 flights · limited

Best day of week

On-time rates are fairly even by day on this route — ranging from 74% to 87% on time.

  • Tuesdays87% on time · p90 35 min · 113 flights · limited
  • Thursdays81% on time · p90 30 min · 121 flights · limited
  • Saturdays79% on time · p90 25 min · 122 flights · limited
  • Wednesdays79% on time · p90 45 min · 117 flights · limited
  • Fridays78% on time · p90 30 min · 121 flights · limited
  • Mondays78% on time · p90 35 min · 121 flights · limited
  • Sundays74% on time · p90 50 min · 121 flights · limited
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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.