OnTimeStats

Historical on-time performance

Washington to Louisville

451 miData through Dec 2025Source: US DOT · BTS

Flights on IAD–SDF arrive on time 85% of the time over the last 12 months.

On-time rate85%arrived within 15 min
p90 delay20 min1 in 10 flights is worse (tail risk)
Cancelled1.0%of scheduled flights

based on 302 flights over the last 12 months. On-time means arriving within 15 minutes (BTS standard).

By airline

How each carrier compares

  • Republic Airways
    On-time85%
    Medianon time
    p9020 min
    Cancel1.0%
    Flights302

Why flights run late

Delay causes

  • Airline32%
  • Weather17%
  • Air traffic (NAS)16%
  • Late aircraft35%
  • 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 → SDF

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 86% to 91% on time.

  • Afternoons91% on time · p90 10 min · 79 flights · limited
  • Mornings89% on time · p90 15 min · 386 flights
  • Evenings86% on time · p90 20 min · 809 flights

Best day of week

On-time rates are fairly even by day on this route — ranging from 83% to 90% on time.

  • Wednesdays90% on time · p90 10 min · 178 flights · limited
  • Tuesdays89% on time · p90 15 min · 177 flights · limited
  • Thursdays89% on time · p90 15 min · 185 flights · limited
  • Fridays88% on time · p90 20 min · 185 flights · limited
  • Sundays86% on time · p90 10 min · 191 flights · limited
  • Saturdays84% on time · p90 35 min · 179 flights · limited
  • Mondays83% on time · p90 25 min · 185 flights · limited
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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.