OnTimeStats

Historical on-time performance

Denver to Ontario

819 miData through May 2026Source: US DOT · BTS

Flights on DEN–ONT arrive on time 74% of the time over the last 12 months.

On-time rate74%arrived within 15 min
p90 delay50 min1 in 10 flights is worse (tail risk)
Cancelled0.3%of scheduled flights

based on 2,656 flights over the last 12 months. On-time means arriving within 15 minutes (BTS standard).

By airline

How each carrier compares

Too close to call — no single carrier is clearly more on-time here.

  • Frontier Airlines
    On-time79%
    Medianon time
    p9045 min
    Cancel0.4%
    Flights520
  • United Airlines
    On-time77%
    Medianon time
    p9045 min
    Cancel0.2%
    Flights867
  • Southwest Airlines
    On-time69%
    Medianon time
    p9050 min
    Cancel0.3%
    Flights1,269

Why flights run late

Delay causes

  • Airline34%
  • Weather1%
  • Air traffic (NAS)8%
  • Late aircraft57%
  • Security0%

Most delay minutes here are attributed to Late aircraft.

When flights don't go

Why flights were cancelled

  • Airline75%
  • Weather0%
  • Air traffic (NAS)25%
  • Security0%

Most cancellations here are attributed to Airline. Shares are among 8 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 DEN → 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 — 87% on time.

  • Mornings87% on time · p90 15 min · 1,650 flights
  • Middays82% on time · p90 30 min · 2,064 flights
  • Afternoons72% on time · p90 40 min · 727 flights
  • Overnights65% on time · p90 65 min · 2,012 flights
  • Evenings65% on time · p90 70 min · 1,951 flights

Best day of week

On-time rates are fairly even by day on this route — ranging from 71% to 79% on time.

  • Wednesdays79% on time · p90 45 min · 1,153 flights
  • Tuesdays78% on time · p90 35 min · 1,152 flights
  • Saturdays74% on time · p90 50 min · 1,043 flights
  • Fridays73% on time · p90 40 min · 1,282 flights
  • Sundays72% on time · p90 50 min · 1,234 flights
  • Thursdays72% on time · p90 55 min · 1,272 flights
  • Mondays71% on time · p90 50 min · 1,268 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.