OnTimeStats

Historical on-time performance

Washington to Houston

1,190 miData through Dec 2025Source: US DOT · BTS

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

On-time rate79%arrived within 15 min
p90 delay35 min1 in 10 flights is worse (tail risk)
Cancelled0.6%of scheduled flights

based on 1,930 flights over the last 12 months. On-time means arriving within 15 minutes (BTS standard).

By airline

How each carrier compares

  • United Airlines
    On-time79%
    Medianon time
    p9035 min
    Cancel0.6%
    Flights1,930

Why flights run late

Delay causes

  • Airline28%
  • Weather13%
  • Air traffic (NAS)32%
  • Late aircraft27%
  • Security0%

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

Over time

On-time trend

By season

On-time rate by month

When to fly

Best time to fly IAD → IAH

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

Best time of day

On-time rates are fairly even by time of day on this route — ranging from 63% to 86% on time.

  • Mornings86% on time · p90 20 min · 2,178 flights
  • Middays84% on time · p90 25 min · 1,154 flights
  • Overnights73% on time · p90 45 min · 763 flights
  • Evenings65% on time · p90 65 min · 1,096 flights
  • Afternoons63% on time · p90 65 min · 123 flights · limited

Best day of week

On-time rates are fairly even by day on this route — ranging from 77% to 81% on time.

  • Tuesdays81% on time · p90 30 min · 763 flights
  • Sundays81% on time · p90 30 min · 760 flights
  • Mondays79% on time · p90 35 min · 761 flights
  • Wednesdays79% on time · p90 30 min · 758 flights
  • Thursdays78% on time · p90 40 min · 754 flights
  • Fridays77% on time · p90 35 min · 758 flights
  • Saturdays77% on time · p90 40 min · 760 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.