Route on-time record
DEN to STL: most on-time flights and the best time to fly
Denver (Denver International Airport) to St Louis (St. Louis Lambert International Airport). 3,645 nonstop flights in Jun 2025 to May 2026, 78% arrived within 15 minutes and 0.3% were cancelled. The most reliable flight number was Southwest 2096 at 6:20 AM.
Flying on a specific date? We’ll adjust for the month, the weekday and the forecast.
DEN → STL
Denver to St Louis: 3,645 nonstop flights a year
On time (12 months)
78%
Cancelled
0.3%
avg delay 14 min
Best time to leave
Before 9 AM
94% on time vs 60% 6 to 9 PM
Most reliable airline
Frontier
86% chance on time
Lowest nonstop fare seen in the next two months: $360 (Southwest 1806 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 · Southwest 2096
6:20 AM → 9:25 AM2h 05m nonstop
Local times, typical schedule. Last flown 2026-05-31. Same departure also flew as Southwest 1965; its record covers all of them.
95%
chance on time
- On time (history)
- 99%
- Cancelled
- 1.3%
- Avg arrival delay
- 1 min
- Arrived on time 99% of the time (76 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: 60%).
- Departs outside DEN's trouble window (2 PM to 8 PM, when 79% of its 174 ground stops and delay programs started).
Moderate track record · 76 flights
Find Southwest 2096 fares Opens this date on Aviasales#2 · Southwest 2098
7:35 AM → 10:40 AM2h 05m nonstop
Local times, typical schedule. Last flown 2026-05-29.
90%
chance on time
- On time (history)
- 96%
- Cancelled
- 0.0%
- Avg arrival delay
- 2 min
- Arrived on time 96% of the time (23 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: 60%).
- 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 (23 flights), so its score leans on the airline's record at this hour.
Limited track record · 23 flights
Find Southwest 2098 fares Opens this date on Aviasales#3 · Southwest 4474
7:45 AM → 10:50 AM2h 05m nonstop
Local times, typical schedule. Last flown 2026-05-31. Same departure also flew as Southwest 2378; its record covers all of them.
89%
chance on time
- On time (history)
- 92%
- Cancelled
- 0.0%
- Avg arrival delay
- 8 min
- Arrived on time 92% of the time (36 flights, Jun 2025 to May 2026).
- Never cancelled in 36 scheduled flights.
- Leaves in this route's most on-time window (Before 9 AM: 94% on time; 6 to 9 PM: 60%).
- 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 · 36 flights
Find Southwest 4474 fares Opens this date on Aviasales#4 · Frontier 3302
4:15 PM → 7:23 PM2h 08m nonstop
Local times, typical schedule. Last flown 2026-05-31.
88%
chance on time
- On time (history)
- 89%
- Cancelled
- 0.0%
- Avg arrival delay
- 5 min
- Arrived on time 89% of the time (264 flights, Jun 2025 to May 2026).
- Never cancelled in 264 scheduled flights.
- Departs inside DEN's trouble window: 79% of its 174 ground stops and delay programs started between 2 PM and 8 PM.
Strong track record · 264 flights
Find Frontier 3302 fares Opens this date on Aviasales#5 · Southwest 990
8:20 AM → 11:25 AM2h 05m nonstop
Local times, typical schedule. Last flown 2026-05-27.
87%
chance on time
- On time (history)
- 94%
- Cancelled
- 0.0%
- Avg arrival delay
- 3 min
- Arrived on time 94% of the time (16 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: 60%).
- 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 (16 flights), so its score leans on the airline's record at this hour.
Limited track record · 16 flights
Find Southwest 990 fares Opens this date on Aviasales#6 · United 1315
1:48 PM → 4:56 PM2h 08m nonstop
Local times, typical schedule. Last flown 2026-05-20.
86%
chance on time
- On time (history)
- 86%
- Cancelled
- 0.0%
- Avg arrival delay
- 9 min
- Arrived on time 86% of the time (287 flights, Jun 2025 to May 2026).
- Never cancelled in 288 scheduled flights.
- 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 · 287 flights
Find United 1315 fares Opens this date on Aviasales#7 · United 1639
1:25 PM → 4:33 PM2h 08m nonstop
Local times, typical schedule. Last flown 2026-05-31.
84%
chance on time
- On time (history)
- 82%
- Cancelled
- 0.0%
- Avg arrival delay
- 11 min
- Arrived on time 82% of the time (11 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 (11 flights), so its score leans on the airline's record at this hour.
Limited track record · 11 flights
Find United 1639 fares Opens this date on Aviasales#8 · United 652
10:00 AM → 1:08 PM2h 07m nonstop
Local times, typical schedule. Last flown 2026-05-31. Same departure also flew as United 1084; its record covers all of them.
83%
chance on time
- On time (history)
- 83%
- Cancelled
- 0.3%
- Avg arrival delay
- 9 min
- Arrived on time 83% of the time (363 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).
Strong track record · 363 flights
Find United 652 fares Opens this date on Aviasales#9 · Southwest 2813
3:50 PM → 6:50 PM2h 00m nonstop
Local times, typical schedule. Last flown 2026-04-06.
83%
chance on time
- On time (history)
- 83%
- Cancelled
- 0.0%
- Avg arrival delay
- 8 min
- Arrived on time 83% of the time (93 flights, Jun 2025 to May 2026).
- Never cancelled in 93 scheduled flights.
- Departs inside DEN's trouble window: 79% of its 174 ground stops and delay programs started between 2 PM and 8 PM.
Moderate track record · 93 flights
Find Southwest 2813 fares Opens this date on Aviasales#10 · Southwest 2490
10:30 AM → 1:35 PM2h 05m nonstop
Local times, typical schedule. Last flown 2026-05-31. Same departure also flew as Southwest 3159; its record covers all of them.
82%
chance on time
- On time (history)
- 82%
- Cancelled
- 0.0%
- Avg arrival delay
- 8 min
- Arrived on time 82% of the time (87 flights, Jun 2025 to May 2026).
- Never cancelled in 88 scheduled flights.
- Departs outside DEN's trouble window (2 PM to 8 PM, when 79% of its 174 ground stops and delay programs started).
Moderate track record · 87 flights
Find Southwest 2490 fares Opens this date on Aviasales
Airlines on this route
Season-adjusted chance of operating and arriving on time.
- Frontier Airlines86%
264 flights · 89% on time as flown · 0.1% cancel
- United Airlines79%
1,042 flights · 79% on time as flown · 0.2% cancel
- Southwest Airlines76%
2,168 flights · 76% on time as flown · 0.3% cancel
- SkyWest Airlines (sold as United Express, Delta Connection, American Eagle or Alaska)75%
171 flights · 71% on time as flown · 0.4% cancel
On time by departure time
All airlines, scheduled local departure, Jun 2025 to May 2026.
- Before 9 AM94%
796 flights · avg delay 3 min
- 9 AM to noon84%
820 flights · avg delay 8 min
- Noon to 3 PM81%
628 flights · avg delay 12 min
- 3 to 6 PM69%
647 flights · avg delay 20 min
- 6 to 9 PM60%
698 flights · avg delay 29 min
Best day: Tuesday (79%). Worst: Sunday (74%).
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)27%
- Air traffic control and airport volume14%
- 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
DEN to STL questions
- What time of day is best to fly DEN to STL?
- Before 9 AM: 94% of flights arrived on time, against 60% 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 DEN to STL?
- Frontier, with a season-adjusted 86% chance of operating and arriving on time over 264 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 STL?
- June (67% on time); the best was February (83%), 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
- STL 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