Denver (DEN) to Louisville (SDF): On-Time Performance
Data through May 2026
The calendar drives reliability on DEN–SDF. October 2024 flights landed on schedule 89% of the time, but July 2025 dropped to 52% — a gap of 37 points. Across the full period the route averages 74% on-time against a national 78%. Morning departures also hold up better than evening ones (86% vs 66%), which matters most in the rough months.
- On-time
- 74%
- arrived <15 min late
- Avg delay
- 18 min
- completed flights
- Cancelled
- 0.7%
- Flights/day
- 3.0
- last 12 months
- Duration
- 2h 36m
- scheduled
- Distance
- 1,024 mi
Best airline from DEN to SDF
2 airlines flew this route regularly between 2024-06 and 2026-05.
| Airline | On-time | Avg delay | Cancelled | Flights |
|---|---|---|---|---|
| United Airlinesmost reliable | 80% | 15 min | 0.6% | 1,399 |
| Southwest Airlines | 65% | 24 min | 0.8% | 751 |
Monthly on-time trend
Best time to fly from DEN to SDF
Aim for departures around 9 a.m. (87% on-time); avoid 9 p.m. departures (48%).
By day of week
| Day | On-time | Avg delay |
|---|---|---|
| Monday | 76% | 13 min |
| Tuesday | 78% | 17 min |
| Wednesday | 75% | 17 min |
| Thursday | 67% | 22 min |
| Friday | 75% | 18 min |
| Saturdaybest | 79% | 15 min |
| Sunday | 71% | 22 min |
What causes delays on this route
Share of total delay minutes by cause, as reported by carriers to the US DOT.
- Late-arriving aircraft51%
- Airline operations31%
- National airspace system16%
- Weather2%
Frequently asked questions
- How often are flights from DEN to SDF delayed?
- 26% of DEN–SDF flights arrived 15 or more minutes late (the US DOT definition of a delay) between 2024-06 and 2026-05. The average arrival delay across completed flights was 18 minutes.
- Which airline is most reliable from DEN to SDF?
- United Airlines has the best on-time record on this route at 80%, based on 1,399 flights. 2 airlines flew DEN–SDF frequently enough to compare in this period.
- What is the best time of day to fly from DEN to SDF?
- Departures around 9 a.m. have the best record (87% on-time), while departures around 9 p.m. have the worst (48%). As on most US routes, delays accumulate through the day, so earlier flights are generally safer.
- How long is the flight from DEN to SDF?
- The scheduled DEN–SDF flight time averages 2h 36m over 1,024 miles. Actual arrival times vary — flights on this route land 15+ minutes late 26% of the time.
- How often are DEN to SDF flights cancelled?
- 0.7% of scheduled flights on this route were cancelled between 2024-06 and 2026-05, at or below the national rate of 1.6%.
- What is the worst month to fly from DEN to SDF?
- July 2025 was the roughest month in this dataset, with only 52% of arrivals on time. The best was October 2024 at 89%. If your dates are flexible, that 37-point gap is worth planning around.
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Based on 2,150 flights, 2024-06–2026-05. Source: US DOT Bureau of Transportation Statistics. Updated 2026-07-01.