OnTimeStats

Airport on-time performance

Ontario

Data through May 2026Source: US DOT · BTS
On-time rate81%flights departing here that arrived on time
p90 delay35 min1 in 10 departures is worse (tail risk)
Cancelled0.9%of scheduled departures
Left the gate on time82%departures that pushed back within 15 min of schedule (DepDel15)

based on 25,874 flights over the last 12 months. On-time means arriving within 15 minutes (BTS standard).

As a connection hub

Arriving here (inbound performance)

These figures reflect inbound flights arriving at this airport — relevant for connections and layovers.

77%arrived on time here
(within 15 min, inbound flights)
  • On time77%
  • 15–59 min late15%
  • 1–2 hr late5%
  • 2 hr+ late2%
  • Cancelled or diverted1%

Arrival outcomes for inbound flights. Last segment = cancelled or diverted.

Bad day: 1 in 10 flights arrives more than 40 min late.

By airline

Carriers departing here (last 12 months)

Delay = arrival delay (ArrDel15-based)

  • SkyWest Airlinesbest
    On-time92%
    Medianon time
    p9010 min
    Cancel0.2%
    Flights1,374
  • Delta Air Lines
    On-time89%
    Medianon time
    p9010 min
    Cancel1.5%
    Flights1,847
  • Alaska Airlines
    On-time83%
    Medianon time
    p9025 min
    Cancel1.7%
    Flights1,876
  • Southwest Airlines
    On-time82%
    Medianon time
    p9030 min
    Cancel0.4%
    Flights11,124
  • United Airlines
    On-time79%
    Medianon time
    p9040 min
    Cancel0.5%
    Flights2,484
  • American Airlines
    On-time78%
    Medianon time
    p9040 min
    Cancel1.9%
    Flights3,597
  • Frontier Airlines
    On-time78%
    Medianon time
    p9060 min
    Cancel1.1%
    Flights1,456
  • JetBlue Airways
    On-time75%
    Medianon time
    p9065 min
    Cancel1.6%
    Flights122

Over time

On-time trend

By season

On-time rate by month

When it gets busy

Busiest times at ONT

Historically, departures at ONT peak 5–10 a.m. — 35% of scheduled flights leave in that block.

  • Midnight–5 a.m.1%
  • 5–10 a.m.35%
  • 10 a.m.–2 p.m.26%
  • 2–5 p.m.14%
  • 5–8 p.m.14%
  • 8 p.m.–midnight10%

Share of 77,260 scheduled departures by planned departure time, 2023-06 .. 2026-05. Historical averages from BTS data — not live airport status.

When flights don't go

Why flights were cancelled

  • Airline45%
  • Weather40%
  • Air traffic (NAS)15%
  • Security0%

Most cancellations here are attributed to Airline. Shares are among 231 cancellations with a reported cause (BTS reports causes from June 2003).

Where flights go

Busiest routes

ONT → PHX→ONT → OAK→ONT → SMF→ONT → LAS→ONT → SJC→ONT → DFW→ONT → DEN→ONT → SFO→ONT → SEA→ONT → SLC→

Side by side

Compare this airport

Compare with Hartsfield Jackson Atlanta International Airporthead-to-head on-time→Compare with Chicago O'Hare International Airporthead-to-head on-time→Compare with Dallas Fort Worth International Airporthead-to-head on-time→Compare with Denver International Airporthead-to-head on-time→

Will you make a connection at ONT? →

Keep exploring

Related guides

When to arrive at the airportguide→Worst airports for delaysguide→

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.