OnTimeStats

Historical on-time performance

Denver to Seattle

1,024 miData through May 2026Source: US DOT · BTS

Flights on DEN–SEA arrive on time 72% of the time over the last 12 months.

On-time rate72%arrived within 15 min
p90 delay50 min1 in 10 flights is worse (tail risk)
Cancelled0.7%of scheduled flights

based on 6,201 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.

  • United Airlines
    On-time79%
    Medianon time
    p9035 min
    Cancel0.6%
    Flights1,904
  • Delta Air Lines
    On-time76%
    Medianon time
    p9055 min
    Cancel1.0%
    Flights840
  • SkyWest Airlines
    On-time76%
    Medianon time
    p9055 min
    Cancel0.5%
    Flights214
  • Alaska Airlines
    On-time72%
    Medianon time
    p9045 min
    Cancel0.9%
    Flights1,571
  • Frontier Airlines
    On-time71%
    Medianon time
    p9060 min
    Cancel1.8%
    Flights329
  • Southwest Airlines
    On-time61%
    Median5 min
    p9055 min
    Cancel0.3%
    Flights1,343

Why flights run late

Delay causes

  • Airline34%
  • Weather2%
  • Air traffic (NAS)17%
  • Late aircraft47%
  • Security0%

Most delay minutes here are attributed to Late aircraft.

When flights don't go

Why flights were cancelled

  • Airline40%
  • Weather44%
  • Air traffic (NAS)16%
  • Security0%

Most cancellations here are attributed to Weather. Shares are among 45 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 → SEA

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 — 86% on time.

  • Mornings86% on time · p90 20 min · 5,393 flights
  • Middays79% on time · p90 35 min · 4,622 flights
  • Afternoons71% on time · p90 45 min · 2,879 flights
  • Evenings63% on time · p90 70 min · 4,183 flights
  • Overnights62% on time · p90 65 min · 2,527 flights

Best day of week

On-time rates are fairly even by day on this route — ranging from 73% to 76% on time.

  • Tuesdays76% on time · p90 40 min · 2,637 flights
  • Wednesdays75% on time · p90 40 min · 2,719 flights
  • Saturdays75% on time · p90 50 min · 2,593 flights
  • Mondays74% on time · p90 45 min · 2,919 flights
  • Sundays74% on time · p90 45 min · 2,872 flights
  • Thursdays73% on time · p90 50 min · 2,927 flights
  • Fridays73% on time · p90 45 min · 2,939 flights

Keep exploring

Related pages

Delay predictorfor this route→DEN airportDenver→SEA airportSeattle→United Airlinesairline profile→Alaska 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.