OnTimeStats

Historical on-time performance

Portland to Ontario

838 miData through May 2026Source: US DOT · BTS

Flights on PDX–ONT arrive on time 81% of the time over the last 12 months.

On-time rate81%arrived within 15 min
p90 delay25 min1 in 10 flights is worse (tail risk)
Cancelled0.3%of scheduled flights

based on 335 flights over the last 12 months. On-time means arriving within 15 minutes (BTS standard).

By airline

How each carrier compares

Not enough comparable data to name a most-on-time carrier — low-data carriers aren't ranked.

  • Alaska Airlines
    On-time82%
    Medianon time
    p9025 min
    Cancel0.3%
    Flights305
  • SkyWest Airlines
    On-time80%
    Medianon time
    p9025 min
    Cancel0.0%
    Flights30

Why flights run late

Delay causes

  • Airline65%
  • Weather1%
  • Air traffic (NAS)11%
  • Late aircraft23%
  • Security1%

Most delay minutes here are attributed to Airline.

When flights don't go

Why flights were cancelled

  • Airline0%
  • Weather0%
  • Air traffic (NAS)100%
  • Security0%

Most cancellations here are attributed to Air traffic (NAS). Shares are among 1 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 PDX → ONT

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 · 308 flights
  • Middays84% on time · p90 20 min · 153 flights · limited
  • Afternoons82% on time · p90 30 min · 511 flights
  • Evenings82% on time · p90 30 min · 482 flights
  • Overnights80% on time · p90 25 min · 259 flights

Best day of week

On-time rates are fairly even by day on this route — ranging from 82% to 86% on time.

  • Tuesdays86% on time · p90 15 min · 187 flights · limited
  • Mondays86% on time · p90 20 min · 278 flights
  • Saturdays86% on time · p90 20 min · 201 flights
  • Fridays83% on time · p90 30 min · 280 flights
  • Thursdays83% on time · p90 25 min · 260 flights
  • Wednesdays83% on time · p90 20 min · 201 flights
  • Sundays82% on time · p90 30 min · 306 flights

Keep exploring

Related pages

Delay predictorfor this route→PDX airportPortland→ONT airportOntario→Alaska Airlinesairline profile→SkyWest Airlinesairline profile→Southwest 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.