Route reliability record
MSO→SLC
Missoula to Salt Lake City
- Flights
- 1,059
- Period
- July 2025 to June 2026
- Distance
- 436 mi
- Carriers
- 2
This route earns an A+. Close to nine flights in ten arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 13 points better than the national rate of 77.6%. When something does go wrong the average delay runs an hour and a half. That rests on 1,059 MSO to SLC flights, of which SkyWest Airlines flew 592 at 91.8% on time.
Best time to fly MSO to SLC: a 11am–2pm departure, ideally on a Monday. Flights in that window arrived on time 91.6% of the time and Monday flights 94.9%, against 90.9% for the route overall.
Set against the rest of the country, this route's record is 13 points better than the US average of 77.6%. That gap is worth roughly 133 fewer late arrivals for every thousand flights.
Key figures
On time
90.9%
Arrivals under 15 minutes late, of 1,048 completed flights
Avg delay
84 min
Across delayed arrivals only, not all flights
Cancelled
0.94%
National rate is 1.81%
Best carrier
SkyWest
91.8% on time across 592 flights
These figures cover 1,059 flights between July 2025 and June 2026. The median arrival is 12 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.
Carrier by carrier
Which airline is most reliable on MSO to SLC
The two carriers here are closely matched: 2 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 | 592 | 91.8% | 47 min | 1.35% | A |
| Delta Air Lines | 467 | 89.9% | 122 min | 0.43% | A+ |
No carrier stands out. SkyWest tops the table at 91.8%, 2 points clear of the bottom, which is inside the range this kind of sample moves year to year.
Flight by flight
Flights on MSO to SLC
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.
Best ways to make this trip
The most reliable ways to fly Missoula to Salt Lake City
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. MSO → SLCMissoula to Salt Lake City | SkyWest Airlines | 90.6% | 91.8% | 1.35% | 11am–2pm, Mon | OO 4112 13:13 |
| 2. MSO → SLCMissoula to Salt Lake City | Delta Air Lines | 89.5% | 89.9% | 0.43% | 5am–8am, Mon | DL 2795 05:30 |
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 is the single lever a traveller controls, and it moves the odds more than most people expect. Each bar below is the on-time rate for flights scheduled to leave inside that window, across 1,059 flights.
- 5am–8am360 flights90.5%
- 8am–11am—
- 11am–2pm354 flights91.6%
- 2pm–5pm5 flights—
- 5pm–8pm340 flights90.6%
- 8pm–5am—
Scale runs 80% to 95%. Rows with fewer than 30 flights show a dash.
The 11am–2pm window is the strongest at 91.6% on time. The full set of windows spans about a point.
Across the year
When delays peak on this route
This route's year swings by 16 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.
Delays peak in March, when the on-time rate falls to 83.3%. June is the strongest month at 98.9%. Moving a flexible trip across that boundary buys 16 points. May was the busiest month here, with 93 flights.
Across the week, Monday is the strongest day at 94.9% on time and Wednesday the weakest at 86.5%. 8 points is a smaller lever than departure hour, but it is free.
Delay causes
Why this route gets delayed
One category carries most of the weight here. Carrier accounts for 57% of the 7,987 delay minutes carriers reported, and the remaining four split what is left. The split is by minutes rather than by flights, so a few very long delays count for as much as many short ones.
- 57%Carrier
- 19%Extreme weather
- 18%Late-arriving aircraft
- 6%National Airspace System
Extreme weather accounts for 19% of delay minutes, well above the single-digit share typical across the system. Weather delays are lumpy: they arrive as whole bad days rather than as a steady drag, so the monthly strip above is the more useful view of the risk. The national share is 6%, so this operation carries roughly 3.0 times the usual weather exposure. The split is drawn from 7,987 reported delay minutes.
The largest share of delay minutes, 57%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. Unlike weather, that is a management outcome, and it is the category where the gap between two carriers on the same schedule is genuinely earned. It accounts for 4,585 of the 7,987 delay minutes reported here.
Cancellations sit at 0.94% against a national 1.81%, which is ordinary. Diversions add another 0.09%.
Connections and stage length
What a delay here actually costs
Badly late arrivals are rare here: only 2.6% land an hour or more behind schedule, against 8.1% nationally. Connections built on this flight are about as safe as US domestic connections get, though a cancelled flight still ignores every layover you give it.
At 436 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 11am–2pm window matters as much as it does.
The return leg runs 88.7% on time across 1,059 flights, within 2 points of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.
One caution: this is a thin sample. 1,059 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.
Work out the risk of missing a connection in SLC after this flight
What to do with this
Booking this route
Put together: treat all of this as provisional. 1,059 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 90.9% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 1,048 completed flights over 12 months sit behind that.
Common questions
MSO to SLC questions
How often is MSO to SLC delayed?
Roughly one flight in ten arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 9.1% of the 1,059 flights in this analysis, against 22.4% nationally. Delayed flights are late by an hour and a half on average.
Which airline is most reliable on MSO to SLC?
SkyWest Airlines leads at 91.8% on time across 592 flights. Delta Air Lines is at the other end on 89.9%, a gap of 2 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 MSO to SLC?
The 11am–2pm departure window is the strongest at 91.6% on time. The 5am–8am window is the weakest at 90.5%, about a point 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 March delays on MSO to SLC?
March is the weakest month at 83.3% on time, compared with 98.9% in June. Across the year that is 16 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
- SLC to MSO — the return legseparate record
- Salt Lake City International (SLC) delay statistics
- SkyWest Airlines on MSO to SLC91.8%
- Delta Air Lines on MSO to SLC89.9%
- MSO to DEN, a related route80.6%
- DEN to SLC, a related route77.5%
- PHX to SLC, a related route83.0%
- SkyWest Airlines on-time record91.8%
- Delta Air Lines on-time record89.9%
- Worst months to fly in the US, ranked by the data
- How to read this site: grades, sample sizes, and honest caveats
Direction matters. MSO to SLC and SLC to MSO 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, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.