STL to DEN flight delays
STL DEN St. Louis Lambert to Denver · 770 miles
11,538 flights were scheduled from STL to DEN over July 2023 through June 2026. Of the 11,428 that made the trip, 77.2% reached the gate less than 15 minutes behind schedule. These are arrival figures: “on time” means the flight reached the gate less than 15 minutes behind schedule. Arrivals are what decide whether you make the connection, so route and airline pages are scored on them rather than on pushback.
Data through June 2026 · Bureau of Transportation Statistics
The route in brief
- Flights in the window
- 11,538
- Arrived on time
- 77.2%
- Cancelled
- 0.8%
- Scheduled distance
- 770 miles
Cancellations are counted against everything scheduled. Diverted flights are counted with them rather than as very late arrivals, which is why the on-time share and the cancellation rate do not add up to everything that happened.
Airline by airline
Airlines with at least 100 flights on STL–DEN, busiest first. Same route, same weather, same air traffic — which makes this the fairest comparison on the site.
| Airline | Arrived on time | Typical delay | Cancelled | Flights |
|---|---|---|---|---|
| Southwest Airlines | 77.1% | 58 min | 0.6% | 6,834 |
| United Airlines | 77.6% | 78 min | 0.9% | 3,407 |
| Frontier Airlines | 73.8% | 91 min | 1.5% | 1,053 |
| SkyWest Airlines | 88.8% | — | 0.4% | 244 |
A dash under typical delay means fewer than 30 of that airline’s flights arrived 15 minutes late or more — too few to average.
Month by month
July was the month to avoid on STL–DEN: 65.7% of flights arrived on time, against 86.2% in November. Each bar pools three years of that calendar month.
| Month | Share flights that arrived on time | Flights |
|---|---|---|
| January | 81.2% | 833 |
| February | 82.3% | 791 |
| March | 78.4% | 950 |
| April | 76.3% | 907 |
| May | 69.2% | 975 |
| June | 67.9% | 1,041 |
| July | 65.7% | 1,086 |
| August | 73.7% | 1,043 |
| September | 83.4% | 993 |
| October | 83.1% | 1,046 |
| November | 86.2% | 927 |
| December | 82.3% | 946 |
Both ends of the route
A route’s record is built out of two airports’ habits. The hour-by-hour grid for each is on its own page.
STL to DEN in one number
STL → DEN
When a flight on this route was late, it was late by about 68 min.
Questions about STL to DEN
- Which airline is most reliable from STL to DEN?
- SkyWest Airlines — its flights on this pairing arrived on time 88.8% of the time, with 244 scheduled. Frontier Airlines came in at 73.8% over 1,053 scheduled. Airlines with fewer than 100 flights on the route are not rated.
- What is the worst month to fly STL to DEN?
- July, at 65.7% of arrivals on time, with 1,086 flights scheduled. November was the best of the year at 86.2%.
- How late are STL–DEN flights when they are late?
- 68 min on average, counting only the flights that arrived 15 minutes or more behind schedule. The on-time flights are left out of that average on purpose — mixing them in would flatter it.
- How often is the STL to DEN flight cancelled?
- 0.8% of scheduled flights on this route were cancelled, July 2023 through June 2026. Diverted flights are counted with the cancellations rather than as late arrivals.
- Are these departure or arrival numbers?
- Arrival. A flight counts as on time here if it reached the gate at DEN less than 15 minutes behind schedule. Airport pages score departures instead, because that is the number you can act on when you pick a booking time.