OnTimeStats

Historical on-time performance

Washington to Las Vegas

2,066 miData through Dec 2025Source: US DOT · BTS

Flights on IAD–LAS arrive on time 79% of the time over the last 12 months.

On-time rate79%arrived within 15 min
p90 delay45 min1 in 10 flights is worse (tail risk)
Cancelled0.2%of scheduled flights

based on 1,222 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
    p9045 min
    Cancel0.2%
    Flights1,161
  • Frontier Airlines
    On-time77%
    Medianon time
    p9080 min
    Cancel0.0%
    Flights61

Why flights run late

Delay causes

  • Airline28%
  • Weather13%
  • Air traffic (NAS)27%
  • Late aircraft32%
  • Security0%

Most delay minutes here are attributed to Late aircraft.

Over time

On-time trend

By season

On-time rate by month

When to fly

Best time to fly IAD → LAS

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 — 88% on time.

  • Mornings88% on time · p90 15 min · 1,217 flights
  • Middays84% on time · p90 25 min · 574 flights
  • Overnights77% on time · p90 50 min · 105 flights · limited
  • Evenings74% on time · p90 60 min · 1,013 flights
  • Afternoons64% on time · p90 45 min · 88 flights · limited

Best day of week

On-time rates are fairly even by day on this route — ranging from 77% to 85% on time.

  • Wednesdays85% on time · p90 25 min · 420 flights
  • Tuesdays85% on time · p90 25 min · 415 flights
  • Saturdays82% on time · p90 30 min · 424 flights
  • Mondays82% on time · p90 30 min · 439 flights
  • Sundays81% on time · p90 45 min · 435 flights
  • Thursdays80% on time · p90 40 min · 431 flights
  • Fridays77% on time · p90 50 min · 433 flights
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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.