80% of flights from Missoula to Seattle arrived on time over the past 12 months. That is about the typical U.S. route. The 7 a.m. departures ran on time 93% of the time; the 4 p.m. ones 77%. 5% of flights arrived more than an hour late or not at all.
How late?
The on-time rate treats a flight 20 minutes late the same as one 5 hours late. Here's the split for MSO → SEA: when a flight was late, it was under 45 minutes late 73% of the time. About 1 in 29 flights landed an hour or more late, and 1 in 130 three hours or more; 1.2% were cancelled outright.
- On time or early80%
- 15–30 min late10%
- 30–60 min late5.7%
- 1–2 hours late2.1%
- 2–3 hours late0.5%
- 3+ hours late0.8%
- Diverted0.1%
- Cancelled1.2%
Share of all 1,168 scheduled flights, past 12 months, by arrival time against schedule.
By airline
| Airline | Flights | On time | Cancelled | Typical arrival | 1h+ late | Avg when late | Operated by |
|---|---|---|---|---|---|---|---|
| Alaska Airlines | 1,168 | 80% | 1.2% | −4 min | 3.4% | +48 min | Alaska Airlines 47%, Horizon Air 42%, SkyWest 11% |
Airline = the name on the ticket. Regional flights (e.g. "Delta Connection") count under the ticketing airline, and the operator is listed.
Best time of day to fly
On-time rate by scheduled departure hour (local time at MSO). Delays build through the day as late planes knock on, so early flights usually do best.
Last flight of the day
On MSO → SEA, each airline's last flight of the day was cancelled 2.2% of the time, against 0.7% for its earlier flights (3.0× as often). It arrived 3+ hours late 0.8% of the time (earlier flights: 0.7%). It matters more than the numbers suggest. Miss an earlier flight and there's another one that evening; miss the last one and you're usually waiting until morning.
| Airline | Last departure | Last: cancelled | Last: 3h+ late | Earlier: cancelled | Next morning |
|---|---|---|---|---|---|
| Alaska Airlines | 7:59 p.m. | 2.2% | 0.8% | 0.7% | first flight 7:03 a.m. |
Last flight = the airline's last scheduled departure on this route that day, on days it flies the route at least twice; past 12 months. Times are typical scheduled times over the latest three months.
If you need to be in SEA tonight, book an earlier flight so there's a backup if it's cancelled.
By month
Each calendar month pooled over 2023–2026. Best: November (87%). Worst: August (71%).
By day of week
| Day | Flights | On time | Cancelled |
|---|---|---|---|
| Monday | 181 | 79% | 1.1% |
| Tuesday | 164 | 81% | 0.0% |
| Wednesday | 159 | 82% | 1.3% |
| Thursday | 173 | 80% | 1.7% |
| Friday | 173 | 71% | 2.9% |
| Saturday | 149 | 87% | 1.3% |
| Sunday | 169 | 78% | 0.0% |
Why flights were late
Share of delay minutes on flights 15+ minutes late, as reported to BTS by the airlines.
Cancellations: weather 6 · airline 5 · air traffic/airport 3
Month by month
Flight numbers on this route
Regular flights with at least 120 scheduled trips in the past year. Sorted by departure time.
| Flight | Departs | Flights | On time | Cancelled | Typical arrival | Operated by |
|---|---|---|---|---|---|---|
| AS 697 | 5:00 p.m. | 120 | 73% | 0.0% | +2 min | Alaska Airlines |
Worst days in the past year
| Date | Flights | On time | Cancelled |
|---|---|---|---|
| Dec 16, 2025 | 3 | 0% | 0 |
| Mar 13, 2026 | 3 | 0% | 1 |
| Mar 27, 2026 | 3 | 0% | 1 |
| Jan 14, 2026 | 3 | 0% | 1 |
| Dec 5, 2025 | 3 | 0% | 0 |
Questions
How often are flights from MSO to SEA on time?
80% of 1,168 scheduled flights from Missoula, MT to Seattle, WA arrived within 15 minutes of schedule between September 2025 and August 2026. 1.2% were cancelled.
What is the best time of day to fly MSO to SEA?
Flights scheduled to leave at 7 a.m. were the most reliable (93% on time). The 4 p.m. departures were the least (77%).
What month has the most delays from MSO to SEA?
August (71% on time). The best month is November (87%), over 2023–2026.
Is the last flight of the day from MSO to SEA more likely to be cancelled?
Yes. Each airline's last MSO–SEA flight of the day was cancelled 2.2% of the time over the past year, against 0.7% for its earlier flights. If the last flight is cancelled, the next one is usually the following morning.
Related
- SEA → MSO (return)
- Missoula Montana (MSO) delays by hour
- Flights into Seattle-Tacoma (SEA)
- Alaska Airlines on-time record
- Connecting off this flight? Check the risk
Domestic flights by the airlines that report to the U.S. DOT, plus their regional partners. "On time" means arriving less than 15 minutes after schedule; cancelled and diverted flights count as not on time. Past performance is a guide, not a forecast. Method.