Route on-time record
SDF to DEN: most on-time flights and the best time to fly
Louisville (Louisville Muhammad Ali International Airport) to Denver (Denver International Airport). 1,107 nonstop flights in Jun 2025 to May 2026, 83% arrived within 15 minutes and 1.1% were cancelled. The most reliable flight number was United 501 at 9:00 AM.
Flying on a specific date? We’ll adjust for the month, the weekday and the forecast.
SDF → DEN
Louisville to Denver: 1,107 nonstop flights a year
On time (12 months)
83%
Cancelled
1.1%
avg delay 12 min
Best time to leave
Before 9 AM
94% on time vs 54% 6 to 9 PM
Most reliable airline
United
84% chance on time
Lowest nonstop fare seen in the next two months: $310 (United 1510 on 2026-10-21). 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 501
9:00 AM → 10:07 AM3h 07m nonstop
Local times, typical schedule. Last flown 2026-05-20. Same departure also flew as United 1180; its record covers all of them.
95%
chance on time
- On time (history)
- 100%
- Cancelled
- 0.0%
- Avg arrival delay
- 1 min
- Arrived on time 100% of the time (53 flights, Jun 2025 to May 2026).
- Never cancelled in 53 scheduled flights.
- Short track record (53 flights), so its score leans on the airline's record at this hour.
Limited track record · 53 flights
Find United 501 fares Opens this date on Aviasales#2 · United 1506
8:00 AM → 8:59 AM2h 59m nonstop
Local times, typical schedule. Last flown 2026-05-31.
89%
chance on time
- On time (history)
- 91%
- Cancelled
- 0.0%
- Avg arrival delay
- 2 min
- Arrived on time 91% of the time (11 flights, Jun 2025 to May 2026).
- Leaves in this route's most on-time window (Before 9 AM: 94% on time; 6 to 9 PM: 54%).
- Short track record (11 flights), so its score leans on the airline's record at this hour.
Limited track record · 11 flights
Find United 1506 fares Opens this date on Aviasales#3 · United 295
8:54 AM → 10:11 AM3h 17m nonstop
Local times, typical schedule. Last flown 2026-03-28.
88%
chance on time
- On time (history)
- 88%
- Cancelled
- 0.0%
- Avg arrival delay
- 6 min
- Arrived on time 88% of the time (24 flights, Jun 2025 to May 2026).
- Leaves in this route's most on-time window (Before 9 AM: 94% on time; 6 to 9 PM: 54%).
- Short track record (24 flights), so its score leans on the airline's record at this hour.
Limited track record · 24 flights
Find United 295 fares Opens this date on Aviasales#4 · Southwest 2137
1:10 PM → 2:05 PM2h 55m nonstop
Local times, typical schedule. Last flown 2026-05-30.
83%
chance on time
- On time (history)
- 90%
- Cancelled
- 0.0%
- Avg arrival delay
- 3 min
- Arrived on time 90% of the time (31 flights, Jun 2025 to May 2026).
- Never cancelled in 31 scheduled flights.
- Lands inside DEN's trouble window: 79% of its 174 ground stops and delay programs started between 2 PM and 8 PM.
- Short track record (31 flights), so its score leans on the airline's record at this hour.
Limited track record · 31 flights
Find Southwest 2137 fares Opens this date on Aviasales#5 · Southwest 1536
1:30 PM → 2:25 PM2h 55m nonstop
Local times, typical schedule. Last flown 2026-04-01.
78%
chance on time
- On time (history)
- 75%
- Cancelled
- 0.0%
- Avg arrival delay
- 7 min
- Arrived on time 75% of the time (8 flights, Jun 2025 to May 2026).
- Lands inside DEN's trouble window: 79% of its 174 ground stops and delay programs started between 2 PM and 8 PM.
- Short track record (8 flights), so its score leans on the airline's record at this hour.
Limited track record · 8 flights
Find Southwest 1536 fares Opens this date on Aviasales#6 · United 1510
3:36 PM → 4:45 PM3h 09m nonstop
Local times, typical schedule. Last flown 2026-05-31.
77%
chance on time
- On time (history)
- 78%
- Cancelled
- 1.1%
- Avg arrival delay
- 15 min
- Arrived on time 78% of the time (359 flights, Jun 2025 to May 2026).
- Lands inside DEN's trouble window: 79% of its 174 ground stops and delay programs started between 2 PM and 8 PM.
Strong track record · 359 flights
Find United 1510 fares Opens this date on Aviasales#7 · Southwest 3328
6:40 PM → 7:30 PM2h 50m nonstop
Local times, typical schedule. Last flown 2026-05-31.
70%
chance on time
- On time (history)
- 65%
- Cancelled
- 0.0%
- Avg arrival delay
- 17 min
- Arrived on time 65% of the time (23 flights, Jun 2025 to May 2026).
- Leaves in this route's least on-time window (6 to 9 PM: 54% on time; Before 9 AM: 94%).
- Lands inside DEN's trouble window: 79% of its 174 ground stops and delay programs started between 2 PM and 8 PM.
- 51% of its delay minutes came from the plane arriving late from an earlier flight.
Limited track record · 23 flights
Find Southwest 3328 fares Opens this date on Aviasales#8 · Southwest 2837
3:35 PM → 4:30 PM2h 55m nonstop
Local times, typical schedule. Last flown 2026-04-06.
69%
chance on time
- On time (history)
- 60%
- Cancelled
- 0.0%
- Avg arrival delay
- 29 min
- Arrived on time 60% of the time (20 flights, Jun 2025 to May 2026).
- Lands inside DEN's trouble window: 79% of its 174 ground stops and delay programs started between 2 PM and 8 PM.
- 65% of its delay minutes came from the plane arriving late from an earlier flight.
- Short track record (20 flights), so its score leans on the airline's record at this hour.
Limited track record · 20 flights
Find Southwest 2837 fares Opens this date on Aviasales
Airlines on this route
Season-adjusted chance of operating and arriving on time.
- United Airlines84%
731 flights · 85% on time as flown · 1.1% cancel
- Southwest Airlines79%
376 flights · 79% on time as flown · 1.1% cancel
On time by departure time
All airlines, scheduled local departure, Jun 2025 to May 2026.
- Before 9 AM94%
315 flights · avg delay 6 min
- 9 AM to noon89%
223 flights · avg delay 8 min
- Noon to 3 PM81%
75 flights · avg delay 9 min
- 3 to 6 PM76%
433 flights · avg delay 16 min
- 6 to 9 PM54%
61 flights · avg delay 28 min
Best day: Tuesday (87%). Worst: Sunday (78%).
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
- Airline (crew, maintenance, boarding)41%
- Air traffic control and airport volume31%
- Late-arriving aircraft25%
- Severe weather3%
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
SDF to DEN questions
- What time of day is best to fly SDF to DEN?
- Before 9 AM: 94% of flights arrived on time, against 54% for departures 6 to 9 PM. Later flights inherit delays from earlier ones, so the first departures of the day usually run best.
- Which airline is most on time from SDF to DEN?
- United, with a season-adjusted 84% 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 SDF to DEN?
- June (76% on time); the best was September (89%), 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 SDF
- DEN to SDF (return)
- SDF to ORD 79%
- SDF to ATL 89%
- SDF to DFW 74%
- SDF to CLT 82%
- SDF to DTW 82%
- SDF to LGA 83%
- SDF to DCA 79%
- SDF to MDW 85%
- SDF to EWR 86%
- SDF to BWI 86%
- SDF to MCO 81%
- SDF to BOS 70%
Live status: FAA delays and ground stops