Route profile
MDW→SDF
Flight reliability, delays and best times to fly from Chicago to Louisville. · 271 miles
Right now
Current conditions at both ends of this route.
Aviation weather is not currently a factor.
FlyerIntel does not currently have live operational data for this airport.
Airport conditions describe the airfield, not any individual flight. An airport operating normally is not a guarantee that a specific flight will depart on time.
Route reliability
July 2023 – June 2026
Better than 67% of comparable major US routes (4,577 compared)
Calculated from 3,077 flights. How this is calculated
Source: US DOT Bureau of Transportation Statistics · Data covering July 2023 – June 2026
Best time to fly
On-time arrival rate by scheduled local departure time.
MDW → SDF flights departing 5–9 AM arrived on time 92.3% of the time, against 60.0% for 9 PM–5 AM departures — a gap of 32.3 percentage points.
By departure window
By departure hour
Source: FlyerIntel analysis of US DOT BTS data · July 2023 – June 2026 · Buckets with fewer than 120 flights are not scored.
Airlines on this route
Performance by the carrier that actually operated the flight.
| Carrier | Flights | On time | Cancelled | Median delay | Severe |
|---|---|---|---|---|---|
| Southwest Airlines | 3,077 | 80.3% | 1.10% | -6 min | 6.0% |
Source: FlyerIntel analysis of US DOT BTS data · July 2023 – June 2026 · Carriers with fewer than 200 flights on this route are not listed.
Weekly and seasonal patterns
By day of week
Tuesday is historically the most reliable day and Thursday the least, a gap of 6.5 percentage points.
By month
July is historically the weakest month and November the strongest, a spread of 27.4 percentage points.
Historical trend
On-time arrival rate by month.
Over the most recent 12 months (2025-07 to 2026-06), on-time arrivals averaged 80.6% against 79.9% in the 12 months before — broadly unchanged.
Source: FlyerIntel analysis of US DOT BTS data · July 2023 – June 2026
Data and methodology
All figures on this page are calculated by FlyerIntel from 3,077 MDW → SDF flight records published by the US DOT Bureau of Transportation Statistics, covering July 2023 – June 2026. A flight is counted as delayed when it arrives 15 or more minutes after its scheduled arrival time, following BTS methodology. Cancelled and diverted flights have no arrival time and are excluded from on-time rates rather than counted as late.