Miami (MIA) to Seattle (SEA): On-Time Performance
Data through May 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 67% on-time against a national 78%.
- On-time
- 67%
- arrived <15 min late
- Avg delay
- 23 min
- completed flights
- Cancelled
- 1.2%
- Flights/day
- 3.2
- last 12 months
- Duration
- 6h 46m
- scheduled
- Distance
- 2,724 mi
Best airline from MIA to SEA
3 airlines flew this route regularly between 2024-06 and 2026-05.
| Airline | On-time | Avg delay | Cancelled | Flights |
|---|---|---|---|---|
| Alaska Airlinesmost reliable | 68% | 18 min | 1.5% | 785 |
| American Airlines | 68% | 21 min | 0.9% | 776 |
| Delta Air Lines | 63% | 31 min | 1.1% | 529 |
Monthly on-time trend
Best time to fly from MIA to SEA
Aim for departures around 7 p.m. (70% on-time); avoid 8 p.m. departures (64%).
By day of week
| Day | On-time | Avg delay |
|---|---|---|
| Monday | 66% | 23 min |
| Tuesdaybest | 75% | 14 min |
| Wednesday | 71% | 12 min |
| Thursday | 64% | 26 min |
| Friday | 64% | 24 min |
| Saturday | 67% | 25 min |
| Sunday | 63% | 33 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 system20%
- Weather6%
- Security2%
Frequently asked questions
- How often are flights from MIA to SEA delayed?
- 33% of MIA–SEA flights arrived 15 or more minutes late (the US DOT definition of a delay) between 2024-06 and 2026-05. The average arrival delay across completed flights was 23 minutes.
- Which airline is most reliable from MIA to SEA?
- Alaska Airlines has the best on-time record on this route at 68%, based on 785 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 7 p.m. have the best record (70% 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 33% of the time.
- How often are MIA to SEA flights cancelled?
- 1.2% of scheduled flights on this route were cancelled between 2024-06 and 2026-05, 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 2,090 flights, 2024-06–2026-05. Source: US DOT Bureau of Transportation Statistics. Updated 2026-07-01.