Miami (MIA) to Seattle (SEA): On-Time Performance
Data through July 2026
The calendar drives reliability on MIA–SEA. October 2024 flights landed on schedule 85% of the time, but March 2026 dropped to 46% — a gap of 39 points. Across the full period the route averages 68% on-time against a national 78%. Morning departures also hold up better than evening ones (83% vs 67%), which matters most in the rough months.
- On-time
- 68%
- arrived <15 min late
- Avg delay
- 21 min
- completed flights
- Cancelled
- 1.1%
- Flights/day
- 3.3
- last 12 months
- Duration
- 6h 46m
- scheduled
- Distance
- 2,724 mi
Best airline from MIA to SEA
3 airlines flew this route regularly between 2024-07 and 2026-07.
| Airline | On-time | Avg delay | Cancelled | Flights |
|---|---|---|---|---|
| American Airlinesmost reliable | 70% | 19 min | 0.7% | 868 |
| Alaska Airlines | 69% | 17 min | 1.3% | 816 |
| Delta Air Lines | 65% | 29 min | 1.2% | 591 |
Monthly on-time trend
Best time to fly from MIA to SEA
Aim for departures around 8 a.m. (93% on-time); avoid 8 p.m. departures (64%).
By day of week
| Day | On-time | Avg delay |
|---|---|---|
| Monday | 65% | 23 min |
| Tuesdaybest | 76% | 13 min |
| Wednesday | 73% | 12 min |
| Thursday | 66% | 22 min |
| Friday | 66% | 22 min |
| Saturday | 70% | 23 min |
| Sunday | 64% | 32 min |
What causes delays on this route
Share of total delay minutes by cause, as reported by carriers to the US DOT.
- Late-arriving aircraft32%
- Airline operations40%
- National airspace system21%
- Weather5%
- Security2%
Frequently asked questions
- How often are flights from MIA to SEA delayed?
- 32% of MIA–SEA 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 21 minutes.
- Which airline is most reliable from MIA to SEA?
- American Airlines has the best on-time record on this route at 70%, based on 868 flights. 3 airlines flew MIA–SEA frequently enough to compare in this period.
- What is the best time of day to fly from MIA to SEA?
- Departures around 8 a.m. have the best record (93% on-time), while departures around 8 p.m. have the worst (64%). As on most US routes, delays accumulate through the day, so earlier flights are generally safer.
- How long is the flight from MIA to SEA?
- The scheduled MIA–SEA flight time averages 6h 46m over 2,724 miles. Actual arrival times vary — flights on this route land 15+ minutes late 32% of the time.
- How often are MIA to SEA flights cancelled?
- 1.1% 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 MIA to SEA?
- March 2026 was the roughest month in this dataset, with only 46% of arrivals on time. The best was October 2024 at 85%. If your dates are flexible, that 39-point gap is worth planning around.
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Based on 2,275 flights, 2024-07–2026-07. Source: US DOT Bureau of Transportation Statistics. Updated 2026-09-28.