OnTimeStats

Historical on-time performance

Washington to Los Angeles

2,288 miData through May 2026Source: US DOT · BTS

Flights on IAD–LAX arrive on time 80% of the time over the last 12 months.

On-time rate80%arrived within 15 min
p90 delay30 min1 in 10 flights is worse (tail risk)
Cancelled0.8%of scheduled flights

based on 2,385 flights over the last 12 months. On-time means arriving within 15 minutes (BTS standard).

By airline

How each carrier compares

Not enough comparable data to name a most-on-time carrier — low-data carriers aren't ranked.

  • United Airlines
    On-time81%
    Medianon time
    p9030 min
    Cancel0.9%
    Flights2,293
  • American Airlines
    On-time74%
    Medianon time
    p9040 min
    Cancel0.0%
    Flights31
  • Alaska Airlines
    On-time41%
    Median20 min
    p90125 min
    Cancel0.0%
    Flights61

Why flights run late

Delay causes

  • Airline36%
  • Weather12%
  • Air traffic (NAS)19%
  • Late aircraft33%
  • Security0%

Most delay minutes here are attributed to Airline.

When flights don't go

Why flights were cancelled

  • Airline60%
  • Weather40%
  • Air traffic (NAS)0%
  • Security0%

Most cancellations here are attributed to Airline. Shares are among 20 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 IAD → LAX

All airlines · rolling 36 months (2023-06 .. 2026-05).

Best time of day

Middays are the most reliable time of day to fly this route — 90% on time.

  • Middays90% on time · p90 10 min · 1,122 flights
  • Mornings86% on time · p90 15 min · 2,134 flights
  • Afternoons81% on time · p90 30 min · 744 flights
  • Overnights79% on time · p90 35 min · 1,221 flights
  • Evenings72% on time · p90 60 min · 2,298 flights

Best day of week

On-time rates are fairly even by day on this route — ranging from 78% to 84% on time.

  • Tuesdays84% on time · p90 20 min · 1,030 flights
  • Wednesdays82% on time · p90 30 min · 1,050 flights
  • Mondays82% on time · p90 25 min · 1,101 flights
  • Fridays81% on time · p90 30 min · 1,124 flights
  • Thursdays79% on time · p90 30 min · 1,111 flights
  • Saturdays78% on time · p90 35 min · 999 flights
  • Sundays78% on time · p90 45 min · 1,104 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.