Route reliability record
DEN→MSO
Denver to Missoula
- Flights
- 1,198
- Period
- September 2025 to August 2026
- Distance
- 679 mi
- Carriers
- 3
This route lands a B+, 4 points better than the national rate of 77.3%. Roughly one flight in five arrives 15 minutes late or worse, and those flights are late by about an hour on average. That rests on 1,198 DEN to MSO flights, of which SkyWest Airlines flew 473 at 85.0% on time.
Best time to fly DEN to MSO: a 5am–8am departure, ideally on a Tuesday. Flights in that window arrived on time 94.0% of the time and Tuesday flights 83.9%, against 81.5% for the route overall.
Set against the rest of the country, this route's record is 4 points better than the US average of 77.3%. That gap is worth roughly 42 fewer late arrivals for every thousand flights.
Key figures
On time
81.5%
Arrivals under 15 minutes late, of 1,189 completed flights
Avg delay
57 min
Across delayed arrivals only, not all flights
Cancelled
0.33%
National rate is 1.89%
Best carrier
SkyWest
85.0% on time across 473 flights
These figures cover 1,198 flights between September 2025 and August 2026. The median arrival is 5 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
Which airline is most reliable on DEN to MSO
The two carriers here are closely matched: 6 points separate the best from the worst. At that spread, schedule and price are better tie-breakers than reliability. Sample sizes are shown so you can see which rows are worth weighing.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| SkyWest Airlines | 473 | 85.0% | 68 min | 0.63% | A+ |
| United Airlines | 717 | 79.2% | 52 min | 0.14% | B+ |
| Frontier Airlinesthin sample | 8 | 75.0% | 49 min | 0.00% | B+ |
No carrier stands out. SkyWest tops the table at 85.0%, 6 points clear of the bottom, which is inside the range this kind of sample moves year to year.
Flight by flight
Flights on DEN to MSO
The flight numbers below flew this route at least 250 times in the period, busiest first. Each has its own record, with its schedule and delay causes.
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Best ways to make this trip
The most reliable ways to fly Denver to Missoula
Every airline on this route, ranked by how often a scheduled flight actually operated and arrived on time, with its best departure time and most punctual flight number. No nearby airport pair beat these.
| Option | Airline | Success | On time | Cancelled | Best departure | Most punctual flight |
|---|---|---|---|---|---|---|
| 1. DEN → MSODenver to Missoula | SkyWest Airlines | 84.5% | 85.0% | 0.63% | 5am–8am, Sat | — |
| 2. DEN → MSODenver to Missoula | United Airlines | 79.1% | 79.2% | 0.14% | 11am–2pm, Tue | UA 1092 19:20 |
Success is the share of scheduled flights that operated and arrived less than 15 minutes late, so a cancelled flight counts against it. “(route)” means the best time comes from every carrier on the route rather than this airline alone.
Departure window
The best time of day to leave
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 19 points, against 6 points between the best and worst carrier.
- 5am–8am117 flights94.0%
- 8am–11am6 flights—
- 11am–2pm558 flights82.1%
- 2pm–5pm160 flights85.5%
- 5pm–8pm357 flights74.9%
- 8pm–5am—
Scale runs 65% to 100%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 94.0% of the time, against 74.9% for the evening window. That is 19 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 11am–2pm window is the busiest, with 558 flights scheduled in it.
Explore
Filter DEN to MSO by airline, time, month and day
Pick a breakdown and a carrier. The dashed mark on each row is the same slice for every US flight.
On DEN to MSO, the best departure window is 5am–8am at 94.0% on time and the worst is 5pm–8pm at 74.9%, a wide gap of 19.1 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am94.0%
- 8–11am—
- 11am–2pm82.1%
- 2–5pm85.5%
- 5–8pm74.9%
- 8pm–5am—
best all US flightsScale 60% to 100%. Cells under 30 flights show a dash.
Across the year
When delays peak on this route
This route's year swings by 24 points from best month to worst, which is wide. An annual average tells you very little about the week you are actually flying, so read the strip rather than the headline if your dates are fixed.
December is the weak month at 66.3% on time, against 89.9% in November. Winter delays cluster: a single storm system can account for most of a month's shortfall, so an average December hides both very good weeks and genuinely unflyable days. August was the busiest month here, with 124 flights.
Across the week, Tuesday is the strongest day at 83.9% on time and Monday the weakest at 77.9%, a spread of 6 points.
Delay causes
Why this route gets delayed
Late-arriving aircraft accounts for 44% of the 12,000 delay minutes carriers reported here, and the remaining four split what is left.
- 44%Late-arriving aircraft
- 36%Carrier
- 17%National Airspace System
- 3%Extreme weather
44% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 12,000 reported delay minutes here, that single category outweighs weather by 13 to one. The split is drawn from 12,487 reported delay minutes.
The largest share of delay minutes, 36%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 4,469 of the 12,000 delay minutes reported here.
Cancellations are rare at 0.33%, 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 actually costs
5.7% 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 about an hour, 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 runs 81.1% on time across 1,198 flights, within half a point of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.
The sample behind these figures is 1,198 flights, enough that the headline rate is stable to within roughly a point. The hour-block and month splits divide that further, so read the thinner bars with more caution than the headline.
Work out the risk of missing a connection in MSO after this flight
What to do with this
Booking this route
Put together: the calendar is the biggest lever here, not the carrier or the hour. November runs 89.9% on time and December 66.3%, a swing of 24 points. If the dates move at all, move them out of December before you think about anything else. 1,189 completed flights over 12 months sit behind that.
Common questions
DEN to MSO questions
How often is DEN to MSO delayed?
Roughly one flight in five arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 18.5% of the 1,198 flights in this analysis, against 22.7% nationally. Delayed flights are late by about an hour on average.
Which airline is most reliable on DEN to MSO?
SkyWest Airlines leads at 85.0% on time across 473 flights. United Airlines is at the other end on 79.2%, a gap of 6 points. Sample size matters as much as the percentage: a rate built from a few hundred flights moves around far more than one built from ten thousand.
What time of day has the fewest delays on DEN to MSO?
The 5am–8am departure window is the strongest at 94.0% on time. The 5pm–8pm window is the weakest at 74.9%, 19 points behind. Later departures inherit delays from earlier flights the same aircraft has already flown, which is why the curve slopes the way it does.
How bad are December delays on DEN to MSO?
December is the weakest month at 66.3% on time, compared with 89.9% in November. Across the year that is 24 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.
Related
Where to go next
- MSO to DEN — the return legseparate record
- Denver International (DEN) delay statistics
- SkyWest Airlines on DEN to MSO85.0%
- United Airlines on DEN to MSO79.2%
- DEN to PHX, a related route75.6%
- SLC to MSO, a related route88.7%
- DEN to SLC, a related route78.2%
- SkyWest Airlines on-time record85.0%
- United Airlines on-time record79.2%
- Frontier Airlines on-time record75.0%
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.05 million flight records
Direction matters. DEN to MSO and MSO to DEN are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
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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.