PlainFlights

Route · MSO → SEA · 2020–2025 BTS data

Missoula to Seattle

According to PlainFlights' route traffic ranking (BTS On-Time Performance total flights), MSO to SEA (Missoula to Seattle) ranks #3336 of 4927 tracked domestic routes by total flights (most flights = #1).

Data updated 2026-06-13

80%
On-time
+1 pts
vs US avg
61 min
Delay when late
2,926
Flights
#3336 of 4927
Corpus placement

Cancelled

1.3%

Best Month

Oct 2022 93%

Worst Month

Dec 2022 57%

Distance

389 mi

Carriers

2

Monthly Performance

Recent 24 months of route data.

Period Flights Delayed Cancelled Diverted Carriers
Dec 2025 61 16 0 0 AS
Nov 2025 59 11 2 0 AS
Oct 2025 36 4 0 0 AS
Aug 2025 31 15 0 0 AS
Jul 2025 31 14 0 0 AS
Jun 2025 30 9 0 0 AS
May 2025 31 10 0 0 AS
Apr 2025 30 6 0 0 AS
Jan 2025 31 11 1 0 AS
Oct 2024 31 11 0 0 AS
Aug 2024 31 8 0 0 AS
Jul 2024 31 6 0 0 AS
Jun 2024 30 8 0 0 AS
Dec 2022 100 43 12 2 QX
Nov 2022 106 37 0 1 QX
Oct 2022 119 8 0 0 QX
Sep 2022 138 22 0 0 QX
Aug 2022 93 16 0 0 QX
Jul 2022 93 17 0 0 QX
Jun 2022 90 16 0 0 QX
May 2022 93 19 2 0 QX
Apr 2022 60 7 1 0 QX
Mar 2022 77 11 1 0 QX
Feb 2022 84 9 1 0 QX

MSO–SEA seasonal on-time pattern

Best: April (93.8%) · weakest: December (66.9%)

60%70%80%90%100% JanFebMarAprMayJunJulAugSepOctNovDec 66.9%

Strongest calendar month

April

93.8% on-time · ~70 flights/mo

Busiest calendar month

September

~129 flights/mo avg

Weakest calendar month

December

66.9% on-time · ~85 flights/mo

Cancellation Rate

1.3%

20 of 1,516 flights

Diversion Rate

0.2%

3 of 1,516 flights

Explore origin & destination

On-time and delay data for the airports this route connects.

MSO - Missoula

Full on-time, delay-cause, and seasonal performance for Missoula, MT.

MSO on-time profile

SEA - Seattle

Full on-time, delay-cause, and seasonal performance for Seattle, WA.

SEA on-time profile

Compare the two airports

See MSO and SEA side by side on delays, cancellations, and reliability.

Compare MSO vs SEA

Origin-hub reliability standing

Mid-pack among MSO departures

From MSO, this corridor sits with 6 other 75–85% on-time routes out of 8 tracked departures, not the hub's reliability leaders (2 at ≥85%) and not the softest ( 0 below 75%). Destination: Seattle · fleet on-time rank #3150 of 4927.

What the Data Says About MSO to SEA

2,926 tracked flights put the MSO to SEA pairing (Missoula to Seattle) at a 80% on-time rate, squarely in line with the wider network. Delays that do occur run 60.7 minutes on average. Across the 389-mile route and its 2 carriers, the trailing 24 months show 1.3% cancelled and 0.2% diverted (1,516 flights sampled).

The monthly split is wide on this route: Oct 2022 posted the strongest performance at 93% on-time, while Dec 2022 came in at just 57% - a 36-point swing worth factoring into travel timing.

On the multi-year calendar, MSO–SEA peaks in April at 93.8% on-time while September carries the heaviest traffic (~129 flights per month) ; the softest month is December at 66.9%, a 26.9-point swing that repeats because the corridor's weather and holiday mix stays stable year to year.

Frequently Asked Questions

Where does MSO to SEA rank among US routes by traffic? ▼
According to PlainFlights' route traffic ranking, MSO to SEA ranks #3336 of 4927 tracked domestic routes by total flights (most flights = #1). That ordinal matches our busiest-routes listing (total_flights DESC). See /methodology#corpus-placement for the exact sort basis.
How often are flights delayed from MSO to SEA? ▼
Flights from Missoula to Seattle have a 80% on-time rate based on 2,926 flights. The average delay is 60.7 minutes. The best recent month was Oct 2022 with 93% on-time.
What is the cancellation rate for MSO to SEA? ▼
Over the last 24 months, 1.3% of flights on this route were cancelled (20 of 1,516 flights) and 0.2% were diverted.
How far is the flight from MSO to SEA? ▼
The flight distance from Missoula (MSO) to Seattle (SEA) is approximately 389 miles. This route is served by 2 carriers.
When is the best time to fly from MSO to SEA? ▼
The best recent month for on-time performance was Oct 2022 (93% on-time). The worst was Dec 2022 (57% on-time). Consider booking during months with historically better performance.

Airports on this route

MSO Airport

Missoula
SEA Airport

Seattle
Data source

Data Source: Bureau of Transportation Statistics (BTS), On-Time Performance Data. Statistics reflect cumulative performance across all available reporting periods.

Read our methodology - how this data is sourced, computed, and verified.

Using MSO–SEA data

MSO–SEA is mid-pack at 80% on-time; month and carrier mix move more than the corridor headline.

  • Compare MSO and SEA airport profiles: delay causes and top routes differ even on the same corridor. MSO airport
  • If your dates flex, April (93.8% on-time) beats December (66.9%) on this corridor. Seasonal chart
  • 4 other routes post a similar 80% on-time rate; compare before you commit to this pairing. Similar routes

On-time rate reflects the BTS historical average across all reporting carriers on this origin–destination pair, not any single flight or booking recommendation.

Data sourced from U.S. Department of Transportation Bureau of Transportation Statistics (BTS) On-Time Performance data. See our methodology for details. Retrieved and formatted by PlainFlights

Every figure on PlainFlights is rendered directly from BTS On-Time Performance data, no number is typed in by an editor. This page aggregates this specific route's on-time performance and monthly trend, live from the dataset. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.