Route on-time record
DEN to SDF: most on-time flights and the best time to fly
Denver (Denver International Airport) to Louisville (Louisville Muhammad Ali International Airport). 1,106 nonstop flights in Jun 2025 to May 2026, 75% arrived within 15 minutes and 0.7% were cancelled. The most reliable flight number was United 1479 at 9:44 AM.
Flying on a specific date? We’ll adjust for the month, the weekday and the forecast.
DEN → SDF
Denver to Louisville: 1,106 nonstop flights a year
On time (12 months)
75%
Cancelled
0.7%
avg delay 18 min
Best time to leave
9 AM to noon
87% on time vs 48% after 9 PM
Most reliable airline
United
79% chance on time
Lowest nonstop fare seen in the next two months: $528 (United 514 on 2026-10-22). Fares open on our travel partner (Aviasales). Pick the flight number you chose here.
Most reliable nonstop flights
Ranked by the chance the flight operates and arrives within 15 minutes of schedule, from Jun 2025 to May 2026 records.
#1 · United 1479
9:44 AM → 2:31 PM2h 46m nonstop
Local times, typical schedule. Last flown 2026-05-31.
87%
chance on time
- On time (history)
- 89%
- Cancelled
- 0.7%
- Avg arrival delay
- 5 min
- Arrived on time 89% of the time (284 flights, Jun 2025 to May 2026).
- Leaves in this route's most on-time window (9 AM to noon: 87% on time; After 9 PM: 48%).
- Departs outside DEN's trouble window (2 PM to 8 PM, when 79% of its 174 ground stops and delay programs started).
Strong track record · 284 flights
Find United 1479 fares Opens this date on Aviasales#2 · United 1293
5:58 PM → 10:39 PM2h 41m nonstop
Local times, typical schedule. Last flown 2026-04-29.
79%
chance on time
- On time (history)
- 88%
- Cancelled
- 0.0%
- Avg arrival delay
- 8 min
- Arrived on time 88% of the time (32 flights, Jun 2025 to May 2026).
- Never cancelled in 32 scheduled flights.
- Departs inside DEN's trouble window: 79% of its 174 ground stops and delay programs started between 2 PM and 8 PM.
- Short track record (32 flights), so its score leans on the airline's record at this hour.
Limited track record · 32 flights
Find United 1293 fares Opens this date on Aviasales#3 · United 421
5:25 PM → 9:59 PM2h 34m nonstop
Local times, typical schedule. Last flown 2026-03-28.
74%
chance on time
- On time (history)
- 71%
- Cancelled
- 0.0%
- Avg arrival delay
- 34 min
- Arrived on time 71% of the time (24 flights, Jun 2025 to May 2026).
- Departs inside DEN's trouble window: 79% of its 174 ground stops and delay programs started between 2 PM and 8 PM.
- 68% of its delay minutes came from the plane arriving late from an earlier flight.
- Short track record (24 flights), so its score leans on the airline's record at this hour.
Limited track record · 24 flights
Find United 421 fares Opens this date on Aviasales#4 · Southwest 2413
11:35 AM → 4:05 PM2h 30m nonstop
Local times, typical schedule. Last flown 2026-05-31.
73%
chance on time
- On time (history)
- 81%
- Cancelled
- 0.0%
- Avg arrival delay
- 8 min
- Arrived on time 81% of the time (53 flights, Jun 2025 to May 2026).
- Never cancelled in 53 scheduled flights.
- Leaves in this route's most on-time window (9 AM to noon: 87% on time; After 9 PM: 48%).
- Departs outside DEN's trouble window (2 PM to 8 PM, when 79% of its 174 ground stops and delay programs started).
Limited track record · 53 flights
Find Southwest 2413 fares Opens this date on Aviasales#5 · United 514
5:50 PM → 10:31 PM2h 41m nonstop
Local times, typical schedule. Last flown 2026-05-31.
71%
chance on time
- On time (history)
- 69%
- Cancelled
- 0.0%
- Avg arrival delay
- 22 min
- Arrived on time 69% of the time (32 flights, Jun 2025 to May 2026).
- Never cancelled in 32 scheduled flights.
- Departs inside DEN's trouble window: 79% of its 174 ground stops and delay programs started between 2 PM and 8 PM.
- Short track record (32 flights), so its score leans on the airline's record at this hour.
Limited track record · 32 flights
Find United 514 fares Opens this date on Aviasales#6 · Southwest 2755
12:55 PM → 5:15 PM2h 20m nonstop
Local times, typical schedule. Last flown 2026-04-06.
70%
chance on time
- On time (history)
- 80%
- Cancelled
- 0.0%
- Avg arrival delay
- 10 min
- Arrived on time 80% of the time (20 flights, Jun 2025 to May 2026).
- Departs outside DEN's trouble window (2 PM to 8 PM, when 79% of its 174 ground stops and delay programs started).
- Short track record (20 flights), so its score leans on the airline's record at this hour.
Limited track record · 20 flights
Find Southwest 2755 fares Opens this date on Aviasales#7 · Southwest 1251
10:25 AM → 2:55 PM2h 30m nonstop
Local times, typical schedule. Last flown 2026-04-01.
67%
chance on time
- On time (history)
- 75%
- Cancelled
- 0.0%
- Avg arrival delay
- 18 min
- Arrived on time 75% of the time (8 flights, Jun 2025 to May 2026).
- Leaves in this route's most on-time window (9 AM to noon: 87% on time; After 9 PM: 48%).
- Departs outside DEN's trouble window (2 PM to 8 PM, when 79% of its 174 ground stops and delay programs started).
- Short track record (8 flights), so its score leans on the airline's record at this hour.
Limited track record · 8 flights
Find Southwest 1251 fares Opens this date on Aviasales
Airlines on this route
Season-adjusted chance of operating and arriving on time.
- United Airlines79%
731 flights · 80% on time as flown · 0.6% cancel
- Southwest Airlines66%
375 flights · 65% on time as flown · 1.0% cancel
On time by departure time
All airlines, scheduled local departure, Jun 2025 to May 2026.
- 9 AM to noon87%
427 flights · avg delay 7 min
- Noon to 3 PM79%
83 flights · avg delay 12 min
- 3 to 6 PM70%
447 flights · avg delay 24 min
- 6 to 9 PM56%
97 flights · avg delay 40 min
- After 9 PM48%
51 flights · avg delay 36 min
Best day: Saturday (78%). Worst: Thursday (67%).
On time by month
All airlines, Jun 2023 to May 2026. Several years per month, so one stormy season doesn't define a month. Travel-month estimates use this seasonal pattern.
What delays this route
- Late-arriving aircraft57%
- Airline (crew, maintenance, boarding)29%
- Air traffic control and airport volume13%
- Severe weather2%
Share of delay minutes by the cause airlines report to the US DOT.
Historical odds, not a guarantee. Built from the US DOT Bureau of Transportation Statistics on-time reports (Jun 2025 to May 2026), FAA ground stop and delay program advisories, and 20 years of airport weather observations. Covers US airlines that report to the DOT; schedules are flights operated recently, so confirm times when you book. ATIS Alerts is not affiliated with any airline. Fares are what Aviasales travelers saw in recent searches (USD, one way, 1 adult), not live quotes; the partner site shows the current price. Fare links go to our travel partner and may earn us a commission at no cost to you. Affiliate disclosure
DEN to SDF questions
- What time of day is best to fly DEN to SDF?
- 9 AM to noon: 87% of flights arrived on time, against 48% for departures after 9 PM.
- Which airline is most on time from DEN to SDF?
- United, with a season-adjusted 79% chance of operating and arriving on time over 731 flights. The adjustment compares each airline with what the route did in the months it flew, so a carrier that skipped a stormy month gets no free credit.
- What is the worst month for delays on DEN to SDF?
- June (60% on time); the best was December (81%), averaged over Jun 2023 to May 2026.
- Is this a prediction for my flight?
- No. These are historical odds from the US DOT on-time reports, FAA advisories and airport weather records. Check your flight status and the FAA delay board on the day you fly.
More routes from DEN
- SDF to DEN (return)
- DEN to PHX 75%
- DEN to SLC 77%
- DEN to LAX 79%
- DEN to LAS 75%
- DEN to SEA 73%
- DEN to ORD 70%
- DEN to DFW 75%
- DEN to SAN 76%
- DEN to MSP 78%
- DEN to ATL 80%
- DEN to SFO 68%
- DEN to AUS 76%
Live status: FAA delays and ground stops