Route on-time record
MIA to SEA: most on-time flights and the best time to fly
Miami (Miami International Airport) to Seattle (Seattle–Tacoma International Airport). 1,150 nonstop flights in Jun 2025 to May 2026, 64% arrived within 15 minutes and 1.2% were cancelled. The most reliable flight number was American 654 at 8:20 AM.
Flying on a specific date? We’ll adjust for the month, the weekday and the forecast.
MIA → SEA
Miami to Seattle: 1,150 nonstop flights a year
On time (12 months)
64%
Cancelled
1.2%
avg delay 25 min
Best time to leave
Before 9 AM
71% on time vs 52% 3 to 6 PM
Most reliable airline
American
67% chance on time
Lowest nonstop fare seen in the next two months: $199 (Alaska 305 on 2026-10-23). 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 · American 654
8:20 AM → 11:57 AM6h 37m nonstop
Local times, typical schedule. Last flown 2026-05-31.
71%
chance on time
- On time (history)
- 82%
- Cancelled
- 0.0%
- Avg arrival delay
- 7 min
- Arrived on time 82% of the time (11 flights, Jun 2025 to May 2026).
- Leaves in this route's most on-time window (Before 9 AM: 71% on time; 3 to 6 PM: 52%).
- Departs outside MIA's trouble window (1 PM to 7 PM, when 49% of its 45 ground stops and delay programs started).
Limited track record · 11 flights
Find American 654 fares Opens this date on Aviasales#2 · American 3252
8:06 PM → 11:44 PM6h 38m nonstop
Local times, typical schedule. Last flown 2026-05-31.
67%
chance on time
- On time (history)
- 68%
- Cancelled
- 0.0%
- Avg arrival delay
- 18 min
- Arrived on time 68% of the time (208 flights, Jun 2025 to May 2026).
- Never cancelled in 209 scheduled flights.
- Departs outside MIA's trouble window (1 PM to 7 PM, when 49% of its 45 ground stops and delay programs started).
Strong track record · 208 flights
Find American 3252 fares Opens this date on Aviasales#3 · Alaska 305
6:04 PM → 10:00 PM6h 56m nonstop
Local times, typical schedule. Last flown 2026-05-31.
62%
chance on time
- On time (history)
- 62%
- Cancelled
- 1.6%
- Avg arrival delay
- 21 min
- Arrived on time 62% of the time (251 flights, Jun 2025 to May 2026).
- Departs inside MIA's trouble window: 49% of its 45 ground stops and delay programs started between 1 PM and 7 PM.
Strong track record · 251 flights
Find Alaska 305 fares Opens this date on Aviasales#4 · Delta 506
5:56 PM → 9:48 PM6h 52m nonstop
Local times, typical schedule. Last flown 2026-05-31.
59%
chance on time
- On time (history)
- 62%
- Cancelled
- 2.1%
- Avg arrival delay
- 38 min
- Arrived on time 62% of the time (273 flights, Jun 2025 to May 2026).
- Leaves in this route's least on-time window (3 to 6 PM: 52% on time; Before 9 AM: 71%).
- Departs inside MIA's trouble window: 49% of its 45 ground stops and delay programs started between 1 PM and 7 PM.
- Lands inside SEA's trouble window: 54% of its 68 ground stops and delay programs started between 4 PM and 10 PM.
Strong track record · 273 flights
Find Delta 506 fares Opens this date on Aviasales
Airlines on this route
Season-adjusted chance of operating and arriving on time.
- American Airlines67%
393 flights · 67% on time as flown · 0.7% cancel
- Alaska Airlines63%
392 flights · 64% on time as flown · 1.4% cancel
- Delta Air Lines61%
365 flights · 61% on time as flown · 1.5% cancel
On time by departure time
All airlines, scheduled local departure, Jun 2025 to May 2026.
- Before 9 AM71%
58 flights · avg delay 15 min
- 3 to 6 PM52%
148 flights · avg delay 39 min
- 6 to 9 PM66%
944 flights · avg delay 23 min
Best day: Tuesday (74%). Worst: Sunday (64%).
Smarter routing
Nearby airports that run more on time
FLL → SEA 66% chance on time
Fort Lauderdale Hollywood International Airport to Seattle–Tacoma International Airport · 826 flights a year · 21 mi from your airports · yours: 64%
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.
What delays this route
- Airline (crew, maintenance, boarding)45%
- Late-arriving aircraft30%
- Air traffic control and airport volume20%
- Severe weather4%
- Security2%
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
MIA to SEA questions
- What time of day is best to fly MIA to SEA?
- Before 9 AM: 71% of flights arrived on time, against 52% for departures 3 to 6 PM. Later flights inherit delays from earlier ones, so the first departures of the day usually run best.
- Which airline is most on time from MIA to SEA?
- American, with a season-adjusted 67% chance of operating and arriving on time over 393 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 MIA to SEA?
- July (57% on time); the best was October (79%), 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.
More routes from MIA
- SEA to MIA (return)
- MIA to ATL 73%
- MIA to LGA 67%
- MIA to DFW 73%
- MIA to JFK 71%
- MIA to ORD 71%
- MIA to EWR 72%
- MIA to DCA 75%
- MIA to MCO 72%
- MIA to IAH 76%
- MIA to CLT 78%
- MIA to BOS 69%
- MIA to LAX 75%
Most on-time flights from MIA on every route →
Live status: FAA delays and ground stops