Denver (DEN) to St. Louis (STL): On-Time Performance
Data through May 2026
Denver (DEN) to St. Louis (STL) effectively runs on two schedules. In October 2024, 88% of arrivals were on time; in July 2025 that fell to 66% — a 22-point seasonal swing. Across the full period the route averages 78% on-time against a national 78%. Morning departures also hold up better than evening ones (89% vs 65%), which matters most in the rough months.
- On-time
- 78%
- arrived <15 min late
- Avg delay
- 14 min
- completed flights
- Cancelled
- 0.5%
- Flights/day
- 10.0
- last 12 months
- Duration
- 2h 5m
- scheduled
- Distance
- 770 mi
Best airline from DEN to STL
4 airlines flew this route regularly between 2024-06 and 2026-05.
| Airline | On-time | Avg delay | Cancelled | Flights |
|---|---|---|---|---|
| Frontier Airlinesmost reliable | 84% | 9 min | 0.7% | 566 |
| United Airlines | 80% | 13 min | 0.6% | 2,131 |
| Southwest Airlines | 77% | 14 min | 0.5% | 4,449 |
| SkyWest Airlines | 69% | 21 min | 1.0% | 201 |
Monthly on-time trend
Best time to fly from DEN to STL
Aim for departures around 5 a.m. (94% on-time); avoid 9 p.m. departures (58%).
By day of week
| Day | On-time | Avg delay |
|---|---|---|
| Monday | 78% | 14 min |
| Tuesdaybest | 81% | 12 min |
| Wednesday | 80% | 11 min |
| Thursday | 79% | 14 min |
| Friday | 77% | 15 min |
| Saturday | 80% | 12 min |
| Sunday | 75% | 16 min |
What causes delays on this route
Share of total delay minutes by cause, as reported by carriers to the US DOT.
- Late-arriving aircraft53%
- Airline operations29%
- National airspace system15%
- Weather2%
Frequently asked questions
- How often are flights from DEN to STL delayed?
- 22% of DEN–STL 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 14 minutes.
- Which airline is most reliable from DEN to STL?
- Frontier Airlines has the best on-time record on this route at 84%, based on 566 flights. 4 airlines flew DEN–STL frequently enough to compare in this period.
- What is the best time of day to fly from DEN to STL?
- Departures around 5 a.m. have the best record (94% on-time), while departures around 9 p.m. have the worst (58%). As on most US routes, delays accumulate through the day, so earlier flights are generally safer.
- How long is the flight from DEN to STL?
- The scheduled DEN–STL flight time averages 2h 5m over 770 miles. Actual arrival times vary — flights on this route land 15+ minutes late 22% of the time.
- How often are DEN to STL flights cancelled?
- 0.5% 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 STL?
- July 2025 was the roughest month in this dataset, with only 66% of arrivals on time. The best was October 2024 at 88%. If your dates are flexible, that 22-point gap is worth planning around.
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Based on 7,347 flights, 2024-06–2026-05. Source: US DOT Bureau of Transportation Statistics. Updated 2026-07-01.