OnTimeStats

Historical on-time performance

Washington to Miami

921 miData through May 2026Source: 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)
Cancelled0.6%of scheduled flights

based on 512 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
    Cancel0.6%
    Flights512

Why flights run late

Delay causes

  • Airline22%
  • Weather1%
  • Air traffic (NAS)46%
  • Late aircraft31%
  • Security0%

Most delay minutes here are attributed to Air traffic (NAS).

When flights don't go

Why flights were cancelled

  • Airline67%
  • Weather33%
  • Air traffic (NAS)0%
  • Security0%

Most cancellations here are attributed to Airline. Shares are among 3 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 → MIA

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

Best time of day

On-time rates are fairly even by time of day on this route — ranging from 67% to 86% on time.

  • Mornings86% on time · p90 20 min · 1,077 flights
  • Middays83% on time · p90 40 min · 150 flights · limited
  • Evenings67% on time · p90 75 min · 359 flights

Best day of week

On-time rates are fairly even by day on this route — ranging from 75% to 84% on time.

  • Tuesdays84% on time · p90 25 min · 214 flights
  • Wednesdays83% on time · p90 25 min · 215 flights
  • Fridays81% on time · p90 35 min · 260 flights
  • Saturdays80% on time · p90 40 min · 252 flights
  • Mondays79% on time · p90 35 min · 262 flights
  • Thursdays79% on time · p90 40 min · 253 flights
  • Sundays75% on time · p90 50 min · 256 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.