OnTimeStats

Historical on-time performance

Washington to Miami

921 miData through Dec 2025Source: US DOT · BTS

Flights on IAD–MIA arrive on time 84% of the time over the last 12 months.

On-time rate84%arrived within 15 min
p90 delay25 min1 in 10 flights is worse (tail risk)
Cancelled0.2%of scheduled flights

based on 455 flights over the last 12 months. On-time means arriving within 15 minutes (BTS standard).

By airline

How each carrier compares

  • United Airlines
    On-time84%
    Medianon time
    p9025 min
    Cancel0.2%
    Flights455

Why flights run late

Delay causes

  • Airline17%
  • Weather3%
  • Air traffic (NAS)39%
  • Late aircraft41%
  • 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 → MIA

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 — 86% on time.

  • Mornings86% on time · p90 20 min · 1,083 flights
  • Afternoons75% on time · p90 50 min · 64 flights · limited
  • Evenings67% on time · p90 75 min · 352 flights

Best day of week

On-time rates are fairly even by day on this route — ranging from 77% to 86% on time.

  • Tuesdays86% on time · p90 20 min · 199 flights · limited
  • Wednesdays82% on time · p90 25 min · 199 flights · limited
  • Mondays81% on time · p90 25 min · 236 flights
  • Thursdays81% on time · p90 35 min · 228 flights
  • Fridays80% on time · p90 35 min · 231 flights
  • Saturdays79% on time · p90 40 min · 226 flights
  • Sundays77% on time · p90 50 min · 234 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.