OnTimeStats

Historical on-time performance

St. Louis to Denver

770 miData through May 2026Source: US DOT · BTS

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

On-time rate74%arrived within 15 min
p90 delay55 min1 in 10 flights is worse (tail risk)
Cancelled0.3%of scheduled flights

based on 3,413 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-time87%
    Medianon time
    p9020 min
    Cancel1.1%
    Flights91
  • SkyWest Airlines
    On-time85%
    Medianon time
    p9020 min
    Cancel0.0%
    Flights122
  • United Airlines
    On-time74%
    Medianon time
    p9065 min
    Cancel0.4%
    Flights1,041
  • Southwest Airlines
    On-time74%
    Medianon time
    p9055 min
    Cancel0.2%
    Flights2,159

Why flights run late

Delay causes

  • Airline23%
  • Weather4%
  • Air traffic (NAS)36%
  • Late aircraft37%
  • Security0%

Most delay minutes here are attributed to Late aircraft.

When flights don't go

Why flights were cancelled

  • Airline70%
  • Weather20%
  • Air traffic (NAS)10%
  • Security0%

Most cancellations here are attributed to Airline. Shares are among 10 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 STL → DEN

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 — 88% on time.

  • Mornings88% on time · p90 15 min · 3,822 flights
  • Middays83% on time · p90 25 min · 2,603 flights
  • Overnights69% on time · p90 60 min · 1,143 flights
  • Afternoons66% on time · p90 80 min · 2,331 flights
  • Evenings60% on time · p90 90 min · 1,625 flights

Best day of week

On-time rates are fairly even by day on this route — ranging from 75% to 79% on time.

  • Wednesdays79% on time · p90 40 min · 1,659 flights
  • Tuesdays79% on time · p90 40 min · 1,590 flights
  • Thursdays77% on time · p90 40 min · 1,679 flights
  • Saturdays76% on time · p90 50 min · 1,427 flights
  • Mondays75% on time · p90 50 min · 1,730 flights
  • Fridays75% on time · p90 55 min · 1,751 flights
  • Sundays75% on time · p90 45 min · 1,688 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.