Seattle (SEA) to Missoula (MSO): On-Time Performance
Data through July 2026
Seattle (SEA) to Missoula (MSO) effectively runs on two schedules. In September 2025, 100% of arrivals were on time; in May 2025 that fell to 42% — a 58-point seasonal swing. Across the full period the route averages 74% on-time against a national 78%.
- On-time
- 74%
- arrived <15 min late
- Avg delay
- 13 min
- completed flights
- Cancelled
- 0.7%
- Flights/day
- 1.7
- last 12 months
- Duration
- 1h 28m
- scheduled
- Distance
- 389 mi
Best airline from SEA to MSO
2 airlines flew this route regularly between 2024-07 and 2026-07.
| Airline | On-time | Avg delay | Cancelled | Flights |
|---|---|---|---|---|
| SkyWest Airlinesmost reliable | 83% | 8 min | 0.0% | 87 |
| Alaska Airlines | 73% | 13 min | 0.8% | 921 |
Monthly on-time trend
Best time to fly from SEA to MSO
Aim for departures around 8 a.m. (89% on-time); avoid 11 a.m. departures (58%).
By day of week
| Day | On-time | Avg delay |
|---|---|---|
| Monday | 70% | 12 min |
| Tuesday | 79% | 8 min |
| Wednesdaybest | 80% | 11 min |
| Thursday | 72% | 17 min |
| Friday | 69% | 13 min |
| Saturday | 77% | 10 min |
| Sunday | 70% | 16 min |
What causes delays on this route
Share of total delay minutes by cause, as reported by carriers to the US DOT.
- Late-arriving aircraft35%
- Airline operations33%
- National airspace system27%
- Weather4%
Frequently asked questions
- How often are flights from SEA to MSO delayed?
- 26% of SEA–MSO flights arrived 15 or more minutes late (the US DOT definition of a delay) between 2024-07 and 2026-07. The average arrival delay across completed flights was 13 minutes.
- Which airline is most reliable from SEA to MSO?
- SkyWest Airlines has the best on-time record on this route at 83%, based on 87 flights. 2 airlines flew SEA–MSO frequently enough to compare in this period.
- What is the best time of day to fly from SEA to MSO?
- Departures around 8 a.m. have the best record (89% on-time), while departures around 11 a.m. have the worst (58%). As on most US routes, delays accumulate through the day, so earlier flights are generally safer.
- How long is the flight from SEA to MSO?
- The scheduled SEA–MSO flight time averages 1h 28m over 389 miles. Actual arrival times vary — flights on this route land 15+ minutes late 26% of the time.
- How often are SEA to MSO flights cancelled?
- 0.7% of scheduled flights on this route were cancelled between 2024-07 and 2026-07, at or below the national rate of 1.6%.
- What is the worst month to fly from SEA to MSO?
- May 2025 was the roughest month in this dataset, with only 42% of arrivals on time. The best was September 2025 at 100%. If your dates are flexible, that 58-point gap is worth planning around.
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Based on 1,008 flights, 2024-07–2026-07. Source: US DOT Bureau of Transportation Statistics. Updated 2026-09-28.