OnTimeStats

Historical on-time performance

Portland to Washington

2,327 miData through Dec 2025Source: US DOT · BTS

Flights on PDX–IAD arrive on time 86% of the time over the last 12 months.

On-time rate86%arrived within 15 min
p90 delay35 min1 in 10 flights is worse (tail risk)
Cancelled0.4%of scheduled flights

based on 245 flights over the last 12 months. On-time means arriving within 15 minutes (BTS standard).

By airline

How each carrier compares

  • United Airlines
    On-time86%
    Medianon time
    p9035 min
    Cancel0.4%
    Flights245

Why flights run late

Delay causes

  • Airline53%
  • Weather3%
  • Air traffic (NAS)8%
  • Late aircraft36%
  • Security0%

Most delay minutes here are attributed to Airline.

Over time

On-time trend

By season

On-time rate by month

When to fly

Best time to fly PDX → IAD

All airlines · rolling 36 months (2023-01 .. 2025-12).

Best time of day

Mornings are the most reliable time of day to fly this route — 92% on time.

  • Mornings92% on time · p90 10 min · 474 flights
  • Overnights84% on time · p90 40 min · 394 flights

Best day of week

On-time rates are fairly even by day on this route — ranging from 84% to 94% on time.

  • Tuesdays94% on time · p90 10 min · 116 flights · limited
  • Wednesdays92% on time · p90 5 min · 128 flights · limited
  • Sundays91% on time · p90 10 min · 138 flights · limited
  • Mondays87% on time · p90 30 min · 120 flights · limited
  • Saturdays85% on time · p90 25 min · 129 flights · limited
  • Thursdays85% on time · p90 20 min · 128 flights · limited
  • Fridays84% on time · p90 30 min · 119 flights · limited
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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.