Washington (IAD) to Louisville (SDF): On-Time Performance
Data through July 2026
Washington (IAD) to Louisville (SDF) is a thinner route than most in this dataset — 236 departures over the past year, roughly 5 a week — so treat these numbers as indicative rather than definitive. Of the flights that did operate, 88% arrived on time, comfortably above the national average of 78%.
- On-time
- 88%
- arrived <15 min late
- Avg delay
- 12 min
- completed flights
- Cancelled
- 1.3%
- Flights/day
- 0.65
- last 12 months
- Duration
- 1h 50m
- scheduled
- Distance
- 451 mi
Monthly on-time trend
Best time to fly from IAD to SDF
Departure time makes little difference on this route — on-time rates stay within a few points across the day.
By day of week
| Day | On-time | Avg delay |
|---|---|---|
| Monday | 83% | 12 min |
| Tuesday | 89% | 6 min |
| Wednesday | 87% | 16 min |
| Thursday | 88% | 23 min |
| Fridaybest | 91% | 11 min |
| Saturday | 90% | 10 min |
| Sunday | 85% | 8 min |
What causes delays on this route
Share of total delay minutes by cause, as reported by carriers to the US DOT.
- Late-arriving aircraft45%
- Airline operations32%
- National airspace system16%
- Weather7%
Frequently asked questions
- How often are flights from IAD to SDF delayed?
- 12% of IAD–SDF flights arrived 15 or more minutes late (the US DOT definition of a delay) between 2024-07 and 2026-07. The average arrival delay across completed flights was 12 minutes.
- What is the best time of day to fly from IAD to SDF?
- Departures around 3 p.m. have the best record (91% on-time), while departures around 6 p.m. have the worst (87%). As on most US routes, delays accumulate through the day, so earlier flights are generally safer.
- How long is the flight from IAD to SDF?
- The scheduled IAD–SDF flight time averages 1h 50m over 451 miles. Actual arrival times vary — flights on this route land 15+ minutes late 12% of the time.
- How often are IAD to SDF flights cancelled?
- 1.3% of scheduled flights on this route were cancelled between 2024-07 and 2026-07, at or below the national rate of 1.6%.
- What is the worst month to fly from IAD to SDF?
- June 2025 was the roughest month in this dataset, with only 70% of arrivals on time. The best was September 2025 at 100%. If your dates are flexible, that 30-point gap is worth planning around.
Explore related pages
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Related guides
Based on 862 flights, 2024-07–2026-07. Source: US DOT Bureau of Transportation Statistics. Updated 2026-09-28.