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Route on-time record

SEA to MSO: most on-time flights and the best time to fly

Seattle (Seattle–Tacoma International Airport) to Missoula (Missoula Montana Airport). 544 nonstop flights in Jun 2025 to May 2026, 82% arrived within 15 minutes and 0.9% were cancelled. The most reliable flight number was Alaska 660 at 12:13 PM.

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SEA → MSO

Seattle to Missoula: 544 nonstop flights a year

On time (12 months)

82%

Cancelled

0.9%

avg delay 9 min

Best time to leave

After 9 PM

84% on time vs 76% 9 AM to noon

Most reliable airline

Alaska

82% chance on time

Check SEA to MSO fares

Fares open on our travel partner (Aviasales). Pick the flight number you chose here.

Most reliable nonstop flights

Ranked by the chance the flight operates and arrives within 15 minutes of schedule, from Jun 2025 to May 2026 records.

  1. #1 · Alaska 660

    12:13 PM → 2:59 PM1h 45m nonstop

    Local times, typical schedule. Last flown 2026-05-31.

    85%

    chance on time

    On time (history)
    88%
    Cancelled
    2.1%
    Avg arrival delay
    8 min
    • Arrived on time 88% of the time (136 flights, Jun 2025 to May 2026).
    • Departs outside SEA's trouble window (4 PM to 10 PM, when 54% of its 68 ground stops and delay programs started).

    Moderate track record · 136 flights

    Find Alaska 660 fares Opens this date on Aviasales

  2. #2 · Alaska 1330

    9:28 PM → 11:59 PM1h 31m nonstop

    Local times, typical schedule. Last flown 2026-05-31.

    82%

    chance on time

    On time (history)
    84%
    Cancelled
    0.0%
    Avg arrival delay
    5 min
    • Arrived on time 84% of the time (19 flights, Jun 2025 to May 2026).
    • Leaves in this route's most on-time window (After 9 PM: 84% on time; 9 AM to noon: 76%).
    • Departs inside SEA's trouble window: 54% of its 68 ground stops and delay programs started between 4 PM and 10 PM.

    Limited track record · 19 flights

    Find Alaska 1330 fares Opens this date on Aviasales

Airlines on this route

Season-adjusted chance of operating and arriving on time.

  • Alaska Airlines82%

    509 flights · 83% on time as flown · 1.0% cancel

On time by departure time

All airlines, scheduled local departure, Jun 2025 to May 2026.

  • 9 AM to noon76%

    46 flights · avg delay 13 min

  • Noon to 3 PM82%

    302 flights · avg delay 10 min

  • After 9 PM84%

    196 flights · avg delay 8 min

Best day: Tuesday (77%). Worst: Friday (68%).

On time by month

All airlines, Jun 2023 to May 2026. Several years per month, so one stormy season doesn't define a month. Travel-month estimates use this seasonal pattern.

J
73
F
75
M
68
A
80
M
69
J
66
J
66
A
55
S
73
O
75
N
81
D
75

What delays this route

  • Late-arriving aircraft42%
  • Airline (crew, maintenance, boarding)33%
  • Air traffic control and airport volume15%
  • Severe weather11%

Share of delay minutes by the cause airlines report to the US DOT.

Historical odds, not a guarantee. Built from the US DOT Bureau of Transportation Statistics on-time reports (Jun 2025 to May 2026), FAA ground stop and delay program advisories, and 20 years of airport weather observations. Covers US airlines that report to the DOT; schedules are flights operated recently, so confirm times when you book. ATIS Alerts is not affiliated with any airline. Fares are what Aviasales travelers saw in recent searches (USD, one way, 1 adult), not live quotes; the partner site shows the current price. Fare links go to our travel partner and may earn us a commission at no cost to you. Affiliate disclosure

Finding the most reliable connections from SEA to MSO…

SEA to MSO questions

What time of day is best to fly SEA to MSO?
After 9 PM: 84% of flights arrived on time, against 76% for departures 9 AM to noon.
Which airline is most on time from SEA to MSO?
Alaska, with a season-adjusted 82% chance of operating and arriving on time over 509 flights. The adjustment compares each airline with what the route did in the months it flew, so a carrier that skipped a stormy month gets no free credit.
What is the worst month for delays on SEA to MSO?
August (55% on time); the best was November (81%), averaged over Jun 2023 to May 2026.
Is this a prediction for my flight?
No. These are historical odds from the US DOT on-time reports, FAA advisories and airport weather records. Check your flight status and the FAA delay board on the day you fly.

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Live status: FAA delays and ground stops