SDF to IAD flight delays & on-time performance
Nonstop flights from Louisville Muhammad Ali International Airport to Washington Dulles International Airport · 451 miles · Aug 2025 – Jul 2026
No FAA-reported ground stops or delays at SDF or IAD right now. Individual flights can still be delayed by the airline; check with your airline for your flight.
Key facts
- Flights from Louisville (SDF) to Washington (IAD) arrived on time 93% of the time in Aug 2025 – Jul 2026, better than the 78% national average.
- 0.4% were cancelled, and 3% arrived an hour or more late.
- Departures scheduled around 5am did best (100% on time); around 10am did worst (90%).
- Wednesday was the most reliable day to fly (100% on time) and Sunday the least (86%).
- The largest source of delay minutes was airline (crew, maintenance, cleaning, fueling) (44%).
Which airline is most on time from SDF to IAD?
Ranked by on-time arrival rate. Regional airlines fly under their partner's brand (e.g. SkyWest for Delta Connection or United Express).
| Airline | On time | Cancelled | Avg delay | 1 hr+ late | Flights |
|---|---|---|---|---|---|
| Republic AirwaysRegional airline operating flights for American Eagle, Delta Connection and United Express. | 94% | 0.4% | 6 min | 3.4% | 233 |
| United Airlines | 33% | 0.0% | 14 min | 0.0% | 3 |
Best time of day to fly
On-time arrival rate by scheduled departure hour (local time).
- 5am100%20 flights
- 6am93%72 flights
- 10am90%89 flights
- 12pm100%15 flights
- 1pm100%37 flights
Best day of the week
On-time arrival rate by day of departure.
- Monday91%0.0% cancelled
- Tuesday97%3.0% cancelled
- Wednesday100%0.0% cancelled
- Thursday94%0.0% cancelled
- Friday89%0.0% cancelled
- Saturday97%0.0% cancelled
- Sunday86%0.0% cancelled
On-time trend by month
Why flights are late
Share of delay minutes by cause, as reported by airlines to the DOT.
- Airline (crew, maintenance, cleaning, fueling)44%
- Extreme weather25%
- Late-arriving aircraft22%
- Air traffic control & airport congestion10%
- Security0%
Why flights are cancelled
Share of cancellations by reason.
- Extreme weather100%
- Airline (crew, maintenance, cleaning, fueling)0%
- Air traffic control & airport congestion0%
- Security0%
SDF to IAD: common questions
- How often are SDF to IAD flights on time?
- 93% of flights arrived less than 15 minutes late in Aug 2025 – Jul 2026, compared with 78% for all US flights.
- How often are flights from Louisville to Washington cancelled?
- 0.4% of scheduled flights were cancelled (1 of 236).
- How long are typical delays?
- Across all flights the average arrival delay was 6 min (early arrivals count as zero). Flights that were late arrived 80 min behind schedule on average, and 3.4% of flights were an hour or more late.
- How long is taxi time at SDF?
- Flights on this route spent 14 min taxiing from the gate to takeoff on average.
Related routes
Return trip: IAD to SDF — 87% on time
More flights from Louisville
Data: U.S. DOT Bureau of Transportation Statistics, Aug 2025 – Jul 2026 (12 months). Latest month published by BTS: July 2026. Route: SDF → IAD, nonstop flights by US airlines that report to the DOT. How we calculate this.