82% of flights leaving Missoula (MSO) arrived on time over the past 12 months, 6 points better than the national average of 76%. About 16 flights leave MSO on a typical day; 0.9% were cancelled. 83% pushed back from the gate on time, so most of the lateness is already there when the flight leaves the gate.
At a glance
- Best hour to fly: 5 a.m. (92% on time). Worst: 4 p.m. (72%).
- Best month: November (86%). Worst: January (76%).
- Most reliable airline here: Delta Air Lines (90%), vs United Airlines at 78%.
- Biggest delay cause: the airlines themselves (35% of delay minutes).
- Year on year: improving (80% → 82%).
How late?
The on-time rate treats a flight 20 minutes late the same as one 5 hours late. Here's the split for flights leaving MSO: when a flight was late, it was under 45 minutes late 58% of the time. About 1 in 19 flights landed an hour or more late, and 1 in 71 three hours or more; 0.9% were cancelled outright.
- On time or early82%
- 15–30 min late6.7%
- 30–60 min late4.8%
- 1–2 hours late2.8%
- 2–3 hours late1.1%
- 3+ hours late1.4%
- Diverted0.4%
- Cancelled0.9%
Share of all 5,931 scheduled flights, past 12 months, by arrival time against schedule.
Best time of day to fly out of MSO
Time of day matters more at MSO than almost anything else you control. Flights scheduled to leave at 5 a.m. arrived on time 92% of the time; at 4 p.m. it was 72%, a 20-point gap. Taken together, early departures (5–9 a.m.) ran 91% on time against 80% for the evening bank (5–10 p.m.). Early planes usually start the day at the airport, so they haven't had a chance to pick up delays elsewhere. By evening a late inbound aircraft, a crew running out of duty hours or an afternoon thunderstorm can push one late flight into the next. Cancellations cluster too: noon departures were cancelled 2.2% of the time, against 0.9% overall.
Hour × month
Combine the two and the spread is wider still. The most reliable combination at MSO was a 5 a.m. departure in September (95% on time); the least, 5 p.m. in August (61%). If you can only move one thing, move the hour. Departure hour usually shifts the odds more than the month does.
Each cell: on-time rate for that departure hour in that calendar month, 2023–2026. Find your travel month, then look along the row for the greenest hour.
Best and worst months
January is the hardest month at MSO, with 76% of flights on time across 2023–2026; November is the best at 86%. Summer (June–August) runs 8 points worse than autumn: heavy schedules, peak loads and afternoon thunderstorms. Winter costs 6 points against autumn. Cancellations peak in January (3.2% of flights).
Airlines at MSO
Alaska Airlines runs 28% of departures from MSO. Among airlines with at least 1,000 departures here, Delta Air Lines was the most reliable (90% on time) and United Airlines the least (78%), a 12-point difference. On a route where both fly, that difference is worth more than a small fare gap.
| Airline | Departures | On time | Left on time | Cancelled | Typical arrival |
|---|---|---|---|---|---|
| Alaska Airlines | 1,679 | 81% | 85% | 1.3% | −5 min |
| United Airlines | 1,566 | 78% | 81% | 0.8% | −5 min |
| Delta Air Lines | 1,550 | 90% | 90% | 0.8% | −12 min |
| American Airlines | 849 | 78% | 76% | 0.4% | −8 min |
| Allegiant Air | 279 | 74% | 77% | 0.7% | −5 min |
Why flights are late at MSO
Airlines report a cause for every flight that arrives 15 or more minutes late. At MSO, 35% of delay minutes came from the airlines themselves: crew, maintenance, cleaning, fueling and baggage. Next is late-arriving aircraft at 30%. Of the 52 cancellations, 40% were blamed on weather.
The average taxi from gate to takeoff is 18 minutes, about typical for a large U.S. airport.
Month by month
Over the latest 12 months 82% of MSO departures were on time, against 80% in the 12 months before, an improvement of 2 points. The best recent month was February 2026 (88%); the worst, August 2026 (76%).
Worst cancellation days
The worst single day in the past year was Wednesday, Dec 17, 2025, when 25% of 12 scheduled departures were cancelled. Days like that are usually a major storm, a system outage or a holiday peak hitting bad weather. No average predicts them, so on a stormy forecast, check your airline's travel waivers.
| Date | Departures | Cancelled | On time |
|---|---|---|---|
| Dec 17, 2025 | 12 | 25% | 58% |
| Jan 14, 2026 | 13 | 23% | 38% |
| Nov 14, 2025 | 14 | 21% | 71% |
| Nov 13, 2025 | 14 | 21% | 71% |
| Jan 3, 2026 | 15 | 20% | 33% |
| Oct 24, 2025 | 17 | 18% | 71% |
| Nov 12, 2025 | 13 | 15% | 85% |
| Mar 15, 2026 | 13 | 15% | 69% |
| May 28, 2026 | 22 | 9% | 82% |
| Nov 8, 2025 | 13 | 8% | 92% |
Last flights of the day
The last flight of the day is a different bet. Across routes from MSO, each airline's final departure was cancelled 1.2% of the time, against 0.7% for its earlier flights (1.6× as often). Late in the day crews run short on duty hours, aircraft arrive late from elsewhere, and with no later flight to fold passengers into, cancelling is easier for the airline. 1.5% of last flights landed 3+ hours late. The riskiest last flight out was United Airlines to Denver (1.4% cancelled).
| Last flight to | Airline | Leaves | Cancelled | 3h+ late | On time |
|---|---|---|---|---|---|
| DEN Denver | United Airlines | 5:20 p.m. | 1.4% | 2.5% | 73% |
| PDX Portland | Alaska Airlines | 5:41 p.m. | 2.4% | 0.8% | 86% |
| SEA Seattle | Alaska Airlines | 7:59 p.m. | 2.2% | 0.8% | 70% |
| MSP Minneapolis | Delta Air Lines | 3:29 p.m. | 0.0% | 2.3% | 86% |
| SLC Salt Lake City | Delta Air Lines | 6:27 p.m. | 0.3% | 0.3% | 91% |
Each airline's last scheduled departure of the day on a route, on days it flies the route at least twice; past 12 months. Riskiest first.
Tips for flying out of MSO
- Book the earliest departure you can live with. At MSO the 5 a.m. flights do best.
- Traveling in January? Leave extra slack for anything that can't move: cruises, weddings, the last connection of the day.
- Choosing between airlines? Delta Air Lines has the better record here.
- Need to arrive tonight? Don't book the last flight out of MSO; the one before it leaves you a backup.
- Delayed already? Most delays at MSO come from the airlines themselves. If your inbound plane is late, your flight will be too, whatever the board says.
Routes from MSO
Where you're going matters too. From MSO, the most reliable busy route was to Denver (DEN, 80% on time) and the least reliable to Seattle (SEA, 80%). Flights into congested airports inherit their delays: an air traffic program at the destination holds planes on the ground here.
Least reliable first. Routes with at least 365 flights a year.
| To | Flights | On time | Cancelled | Typical arrival |
|---|---|---|---|---|
| ORD Chicago | 473 | 74% | 0.9% | −6 min |
| SEA Seattle | 1,168 | 80% | 1.2% | −4 min |
| DEN Denver | 1,198 | 80% | 0.6% | −6 min |
| DFW Dallas | 429 | 81% | 0.7% | −10 min |
| PDX Portland | 486 | 87% | 1.4% | −8 min |
| SLC Salt Lake City | 1,059 | 90% | 0.9% | −12 min |
| MSP Minneapolis | 491 | 91% | 0.6% | −10 min |
Flights into MSO
Arriving rather than leaving? These are the routes into Missoula Montana, least reliable first. The weakest is from Dallas (72% on time).
| From | Flights | On time | Cancelled |
|---|---|---|---|
| DFW Dallas | 429 | 72% | 0.7% |
| MSP Minneapolis | 490 | 77% | 0.6% |
| ORD Chicago | 472 | 79% | 0.4% |
| DEN Denver | 1,198 | 81% | 0.3% |
| SEA Seattle | 1,170 | 84% | 0.9% |
| PDX Portland | 484 | 87% | 0.4% |
| SLC Salt Lake City | 1,059 | 88% | 0.9% |
Questions about MSO delays
What is the best time to fly out of MSO?
Flights scheduled at 5 a.m.: over the past year 92% of MSO departures at that hour arrived on time, against 72% at 4 p.m., the worst hour.
What month has the most flight delays at MSO?
January (76% on time). November is the best month (86%).
Which airline is most on time at MSO?
Delta Air Lines: 90% of its MSO departures arrived on time over the past year. United Airlines had the weakest record at 78%.
Why are flights delayed at MSO?
The biggest cause was the airlines themselves (35% of delay minutes): crew, maintenance, cleaning, fueling and baggage. Then late-arriving aircraft (30%).
How often are flights cancelled at MSO?
0.9% of scheduled departures over the past 12 months, peaking in January at 3.2%.
Hours are scheduled local departure times. "On time" means arriving less than 15 minutes late at the destination; cancelled and diverted flights count as not on time. Method.