Route profile
MIA→SEA
Flight reliability, delays and best times to fly from Miami to Seattle, 2,724 miles.
Right now
Aviation weather is not currently a factor.
Aviation weather is not currently a factor.
Route reliability
July 2023 – July 2026
Better than 11% of comparable major US routes (4,598 compared)
Calculated from 3,026 flights. How this is calculated
MIA → SEA arrives on time 68.2% of the time; the return trip, SEA → MIA, arrives on time 78.2% of the time, a 10.0-point gap between the two directions of the same city pair.
MIA → SEA spends 39.7 minutes on the ground on a 2,724-mile trip: 25.7 minutes from pushback to wheels-up at MIA and 14.0 minutes from touchdown to gate at SEA.
Source: US DOT Bureau of Transportation Statistics · Data covering July 2023 – July 2026
When it goes wrong
July 2023 – July 2026
62 min late
against a median of 0 min early
MIA → SEA has an average that understates its risk: a typical arrival is 0 min early, but the worst tenth are 62 minutes worse than that. If the trip has something unmissable at the end of it, the median is the wrong number to plan against.
Percentiles over 3,026 operations; cancelled and diverted flights are counted separately.
Will your connection be tight enough?
Layovers at SEA after arriving from MIA.
| Connection time | Chance of missing | Reads as |
|---|---|---|
| 30 min | 49% | Likely to miss |
| 45 min | 31% | Likely to miss |
| 60 min | 20% | High risk |
| 90 min | 10% | Some risk |
| 120 min | 5.3% | Some risk |
This is one leg of a connection. Gate changes and the next flight's own schedule matter too. And a connection can fail before delay is even the question — this route cancels 1.29% of the time and diverts 0.43% of the time, which a late arrival never shows up in.
Chance of missing is the share of 2,974 arrivals on this route that landed later than the connection time less 30 minutes to reach the next gate.
The worst tenth of arrivals on this route land at least 62 minutes late (90th-percentile gate arrival delay), over 3,026 operations.
Any other layover length: connection checker.
Best time to fly
MIA → SEA flights departing 5–9 AM arrived on time 87.7% of the time, against 65.3% for 6–9 PM departures, a gap of 22.4 percentage points.
By departure window
By departure hour
- 12 AM to 4 PM: too few flights to score
- 5 PM: 70.7% on time from 914 flights
- 6 PM: 65.6% on time from 784 flights
- 7 PM: 68.8% on time from 590 flights
- 8 PM: 60.3% on time from 467 flights
- 9 PM to 11 PM: too few flights to score
Departure windows with fewer than 120 flights are not scored.
Why MIA → SEA runs late
July 2023 – July 2026
crew, maintenance, boarding and fueling, all within the carrier’s control
the inbound aircraft was late, so this flight started late
airspace and airport capacity, including weather-driven flow control
weather severe enough to stop this flight specifically
screening or terminal security incidents
Share of the delay minutes US DOT attributed to each cause for MIA → SEA. Only delays of 15 minutes or more are attributed.
Airlines on this route
Carriers with at least 200 flights, by the airline that operated each one.
| Carrier | Flights | On time | Cancelled | Median delay | Severe |
|---|---|---|---|---|---|
| American Airlines | 1,253 | 66.7% | 0.64% | 1 min | 12.4% |
| Alaska Airlines | 1,182 | 71.4% | 2.03% | -3 min | 9.2% |
| Delta Air Lines | 591 | 64.8% | 1.18% | 2 min | 10.5% |
American Airlines flew 41.4% of the 3,026 flights listed. Alaska Airlines cancelled 2.03% of its flights here against 0.64% for American Airlines.
Alaska Airlines arrived on time 6.6 percentage points more often than Delta Air Lines on this route.
Flights on this route
Flight numbers with at least 600 operations here and still on the schedule.
| Flight | Scheduled | Operations | On time |
|---|---|---|---|
| AS305 Alaska Airlines | 5:35 PM | 1,019 | 71.9% |
Weekly and seasonal patterns
By day of week
Tuesday is historically the most reliable day and Sunday the least, a gap of 10.7 percentage points.
By month
- Jan: 68.2%
- Feb: 72.4%
- Mar: 56.9%
- Apr: 70.3%
- May: 63.8%
- Jun: 72.4%
- Jul: 63.3%
- Aug: 60.8%
- Sep: 68.4%
- Oct: 79.2%
- Nov: 75.1%
- Dec: 69.6%
March is historically the weakest month and October the strongest, a spread of 22.3 percentage points.
Reliability over time
July 2023 – July 2026
- July 2023: too few flights to score (62)
- August 2023: too few flights to score (62)
- September 2023: too few flights to score (60)
- October 2023: too few flights to score (62)
- November 2023: too few flights to score (60)
- December 2023: too few flights to score (74)
- January 2024: too few flights to score (69)
- February 2024: too few flights to score (58)
- March 2024: too few flights to score (62)
- April 2024: too few flights to score (60)
- May 2024: too few flights to score (62)
- June 2024: too few flights to score (60)
- July 2024: too few flights to score (62)
- August 2024: too few flights to score (62)
- September 2024: too few flights to score (60)
- October 2024: too few flights to score (62)
- November 2024: too few flights to score (68)
- December 2024: too few flights to score (103)
- January 2025: too few flights to score (103)
- February 2025: too few flights to score (84)
- March 2025: too few flights to score (93)
- April 2025: too few flights to score (90)
- May 2025: too few flights to score (93)
- June 2025: too few flights to score (90)
- July 2025: too few flights to score (93)
- August 2025: too few flights to score (93)
- September 2025: too few flights to score (90)
- October 2025: too few flights to score (93)
- November 2025: too few flights to score (96)
- December 2025: 66.9% from 121 flights
- January 2026: too few flights to score (103)
- February 2026: too few flights to score (84)
- March 2026: too few flights to score (93)
- April 2026: too few flights to score (90)
- May 2026: too few flights to score (104)
- June 2026: 81.7% from 120 flights
- July 2026: 74.8% from 125 flights
Over the most recent 12 months (2025-08 to 2026-07), on-time arrivals averaged 66.6% against 72.0% in the 12 months before — declining by 5.4 percentage points.
Data and methodology
Calculated by FlyerIntel from 3,026 MIA → SEA flight records from the US DOT Bureau of Transportation Statistics, covering July 2023 – July 2026. Late means 15 or more minutes past scheduled arrival; cancelled and diverted flights are left out of on-time rates.
Full methodology · Data sources · Report a problem
Related research: How Long a Layover Needs to Be · Two Airlines on One Route · Best Time of Day to Fly From Major US Airports
Analysis last recomputed