OnTimeStats

Historical on-time performance

Ontario to Chicago

1,700 miData through Dec 2025Source: US DOT · BTS

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

On-time rate79%arrived within 15 min
p90 delay35 min1 in 10 flights is worse (tail risk)
Cancelled0.0%of scheduled flights

based on 183 flights over the last 12 months. On-time means arriving within 15 minutes (BTS standard).

By airline

How each carrier compares

  • United Airlines
    On-time79%
    Medianon time
    p9035 min
    Cancel0.0%
    Flights183

Why flights run late

Delay causes

  • Airline39%
  • Weather0%
  • Air traffic (NAS)52%
  • Late aircraft9%
  • Security0%

Most delay minutes here are attributed to Air traffic (NAS).

Over time

On-time trend

By season

On-time rate by month

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Keep exploring

Related pages

Delay predictorfor this route→ONT airportOntario→ORD airportChicago→American Airlines on this routecarrier detail→American Airlinesairline profile→

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.