Carrier route record
UAMSO→DEN
United Airlines · Missoula to Denver
- Flights
- 717
- Period
- September 2025 to August 2026
- Share of route
- 60%
- Carriers
- 3
Historical statistics for September 2025 to August 2026, not live status. For today’s flights, check with United Airlines.
United on MSO to DEN lands a B+, 6 points better than the national rate of 77.3%. About one flight in six arrives 15 minutes late or worse, and those flights are late by an hour and a half on average. That rests on 717 flights, with a median arrival 7 minutes early.
Set against the rest of the country, United's MSO to DEN record is 6 points better than the US average of 77.3%. That gap is worth roughly 58 fewer late arrivals for every thousand flights.
Key figures
On time
83.1%
Arrivals under 15 minutes late, of 711 completed flights
Avg delay
91 min
Across delayed arrivals only, not all flights
Cancelled
0.28%
National rate is 1.89%
Whole route
81.1%
Every carrier on MSO to DEN, 1,198 flights
These figures cover 717 flights between September 2025 and August 2026. The median arrival is 7 minutes early, which is the part an average hides: most flights here are fine, and the on-time rate is decided by a tail of badly late ones. On-time means under 15 minutes late, the DOT's own threshold.
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Carrier by carrier
United against every carrier on MSO to DEN
United flew 717 of the 1,198 flights on MSO to DEN, most of the route. Its 83.1% on time is 2 points better than the route as a whole, which runs 81.1%. Ranked by on-time rate it is number two of three carriers on the route, where the range runs from Frontier at 87.5% to SkyWest at 78.0%. 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 |
|---|---|---|---|---|---|
| Frontier Airlinesthin sample | 8 | 87.5% | 55 min | 0.00% | A+ |
| United Airlines (this page) | 717 | 83.1% | 91 min | 0.28% | B+ |
| SkyWest Airlines | 473 | 78.0% | 98 min | 1.06% | B |
Flight by flight
United flight numbers on MSO to DEN
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Departure window
When United runs best on this route
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 18 points, against half a point between the best and worst carrier.
- 5am–8am358 flights91.9%
- 8am–11am—
- 11am–2pm—
- 2pm–5pm358 flights74.2%
- 5pm–8pm1 flights—
- 8pm–5am—
Scale runs 65% to 95%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 91.9% of the time, against 74.2% for the afternoon window. That is 18 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 5am–8am window is the busiest, with 358 flights scheduled in it.
Across the year
United on MSO to DEN through the year
August is the worst month at 68.9% on time, 26 points below November, the best at 94.9%. 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. January was the busiest month here, with 62 flights.
Across the week, Tuesday is the strongest day at 88.2% on time and Monday the weakest at 77.4%, a spread of 11 points.
Arrival by arrival
How late United on MSO to DEN runs when it is late
United on MSO to DEN often beats the schedule: 233 of 711 completed flights, 33%, arrived 15 minutes or more early. The 120 late arrivals split 37 under half an hour, 37 between 30 and 60 minutes, and 46 an hour or more.
- 15+ min early233 flights32.8%
- Within 15 min358 flights50.4%
- 15–29 min late37 flights5.2%
- 30–59 min late37 flights5.2%
- 1–2 hours late15 flights2.1%
- 2+ hours late31 flights4.4%
Scale runs 0% to 100%.
Share of 711 completed flights by arrival against schedule.
23 of 118 late departures made up the time and arrived on time, 19% of them. 25 flights left on time and still arrived late.
The worst days
Worst days for United on MSO to DEN
The latest arrival of the period was on 22 July 2026, 8 hours 38 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). Three of the five worst days fell in August 2026.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 22 July 2026 | 8 hours 38 minutes | Carrier |
| 8 August 2026 | 8 hours 3 minutes | Late-arriving aircraft |
| 13 August 2026 | 7 hours 57 minutes | National Airspace System |
| 11 January 2026 | 7 hours 54 minutes | Carrier |
| 14 August 2026 | 6 hours 57 minutes | National Airspace System |
Delay causes
Why United runs late on this route
National Airspace System accounts for 43% of the 11,000 delay minutes carriers reported here, and the remaining four split what is left.
- 43%National Airspace System
- 27%Carrier
- 23%Late-arriving aircraft
- 7%Extreme weather
43% of delay minutes are charged to the National Airspace System: air traffic volume, runway configuration, ground stops. No carrier can price its way out of that, which is why airport choice moves the number here more than carrier choice does. That is 4,738 minutes out of 11,000, against a national NAS share of 21%. The split is drawn from 10,949 reported delay minutes.
Cancellations are rare at 0.28%, 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
6.5% of arrivals land an hour or more late, close to the national 8.3%, so a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last an hour and a half, which a normal layover absorbs.
The 679 miles between these two airports put this in the middle of the US network, around two and a half to three hours of block time. That is enough cruise to absorb a ten-minute late pushback and not enough to absorb thirty.
The return leg is a different operation and performs like one: it runs 79.2% on time across 717 flights, 4 points below 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 4 points of difference.
One caution: this is a thin sample. 717 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 United on MSO to DEN
Put together: treat all of this as provisional. 717 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 83.1% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 711 completed flights over 12 months sit behind that.
Related
Where to go next
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.