Carrier route record
WNDEN→MTJ
Southwest Airlines · Denver to Montrose
- Flights
- 429
- Period
- September 2025 to August 2026
- Share of route
- 30%
- Carriers
- 3
Historical statistics for September 2025 to August 2026, not live status. For today’s flights, check with Southwest Airlines.
Southwest on DEN to MTJ sits in the middle of the pack with a C+. About seven flights in ten arrive on time by the DOT's definition, 5 points worse than the national rate of 77.3%. The late ones land about an hour behind schedule. That rests on 429 flights, with a median arrival 3 minutes early.
The national on-time rate over the same period is 77.3%, so Southwest on DEN to MTJ runs 5 points behind the country as a whole. Across a thousand flights that is about 53 extra late arrivals.
Key figures
On time
72.0%
Arrivals under 15 minutes late, of 428 completed flights
Avg delay
61 min
Across delayed arrivals only, not all flights
Cancelled
0.23%
National rate is 1.89%
Whole route
75.4%
Every carrier on DEN to MTJ, 1,424 flights
These figures cover 429 flights between September 2025 and August 2026. Beyond the headline rate, 9.8% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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Carrier by carrier
Southwest against every carrier on DEN to MTJ
Southwest flew 429 of the 1,424 flights on DEN to MTJ, about 30% of it. Its 72.0% on time is 3 points worse than the route as a whole, which runs 75.4%. Ranked by on-time rate it is last of three carriers on the route, where the range runs from SkyWest at 87.1% to Southwest at 72.0%. One of those carriers flew fewer than 365 flights here, so treat their positions as rough.
Only one carrier clears this site's 365-flight floor here, so there is no comparison to draw. The table below is the full picture.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| SkyWest Airlinesthin sample | 101 | 87.1% | 45 min | 0.00% | A+ |
| United Airlines | 894 | 75.8% | 68 min | 0.11% | B+ |
| Southwest Airlines (this page) | 429 | 72.0% | 61 min | 0.23% | C+ |
Timetable by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.
Departure window
When Southwest runs best on this route
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 29 points, against half a point between the best and worst carrier.
- 5am–8am—
- 8am–11am145 flights87.6%
- 11am–2pm58 flights77.6%
- 2pm–5pm46 flights67.4%
- 5pm–8pm180 flights58.7%
- 8pm–5am—
Scale runs 50% to 95%. Rows with fewer than 30 flights show a dash.
The 5pm–8pm window is where this operation falls apart: 58.7% on time, against 87.6% for the 8am–11am slot. By evening the aircraft flying these rotations have absorbed a full day of small delays and there is no slack left to recover in. The 5pm–8pm window is the busiest, with 180 flights scheduled in it.
Across the year
Southwest on DEN to MTJ through the year
August is the worst month at 40.0% on time, 57 points below November, the best at 96.7%. Summer afternoon convection and peak-season schedules land on the same weeks every year, so this is a pattern you can book around rather than a run of bad luck. March was the busiest month here, with 59 flights.
Across the week, Wednesday is the strongest day at 75.5% on time and Sunday the weakest at 66.1%, a spread of 9 points.
Arrival by arrival
How late Southwest on DEN to MTJ runs when it is late
The 120 late arrivals split 45 under half an hour, 33 between 30 and 60 minutes, and 42 an hour or more.
- 15+ min early95 flights22.2%
- Within 15 min213 flights49.8%
- 15–29 min late45 flights10.5%
- 30–59 min late33 flights7.7%
- 1–2 hours late23 flights5.4%
- 2+ hours late19 flights4.4%
Scale runs 0% to 100%.
Share of 428 completed flights by arrival against schedule.
36 of 144 late departures made up the time and arrived on time, 25% of them. 12 flights left on time and still arrived late.
The worst days
Worst days for Southwest on DEN to MTJ
The latest arrival of the period was on 3 August 2026, 3 hours 56 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). The five worst days are spread across August, December, June and March, with no single month standing out.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 3 August 2026 | 3 hours 56 minutes | Carrier |
| 23 August 2026 | 3 hours 35 minutes | None reported |
| 19 December 2025 | 3 hours 31 minutes | Late-arriving aircraft |
| 27 June 2026 | 3 hours 17 minutes | Carrier |
| 6 March 2026 | 3 hours 12 minutes | Late-arriving aircraft |
Delay causes
Why Southwest runs late on this route
Late-arriving aircraft accounts for 53% of the 7,145 delay minutes carriers reported here, and the remaining four split what is left.
- 53%Late-arriving aircraft
- 36%Carrier
- 11%National Airspace System
- 1%Extreme weather
53% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 7,145 reported delay minutes here, that single category outweighs weather by 53 to one. The split is drawn from 7,145 reported delay minutes.
The largest share of delay minutes, 36%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 2,569 of the 7,145 delay minutes reported here.
Cancellations are rare at 0.23%, below the national 1.89% and low enough to earn the plus on the grade. Roughly one flight in 100 is called off; the risk here is arriving late, not not arriving.
Connections and stage length
What a delay here costs
9.8% of arrivals land a full hour or more behind schedule, against 8.3% nationally. Ninety minutes is the honest minimum for a connection here, and two hours if the onward flight is on a separate ticket.
At 197 miles this is a short hop, and stage length matters more than it looks. A flight this short spends under two hours in the air, which leaves almost nothing to claw back a late pushback with. Delay here is decided on the ground, in the turn, which is why the 8am–11am window matters as much as it does.
The return leg is a different operation and performs like one: it runs 81.5% on time across 428 flights, 10 points above this direction. Departure banks, aircraft rotations and the congestion at each end all differ, so scoring the two directions together would average away a real 10 points of difference.
One caution: this is a thin sample. 429 flights over twelve months is enough to clear this site's floor but not enough to pin the rate down tightly, and a single bad week moves it by more than a point. Treat the grade as a rough reading.
What to do with this
Booking Southwest on DEN to MTJ
Put together: treat all of this as provisional. 429 flights over twelve months is enough to clear this site's floor and not enough to be confident to better than a couple of points. The 72.0% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 428 completed flights over 12 months sit behind that.
Related
Where to go next
- DEN to MTJ, every carrier
- Southwest on MTJ to DEN, the return leg
- SkyWest Airlines on DEN to MTJ87.1%
- United Airlines on DEN to MTJ75.8%
- Southwest Airlines network-wide record
- Denver International (DEN) delay statistics
- Flying to ski country: which routes into the mountains run on time
- Why the first flight of the morning is statistically safest
Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.