Route profile
SEA→MIA
Flight reliability, delays and best times to fly from Seattle to Miami, 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 63% of comparable major US routes (4,598 compared)
Calculated from 3,023 flights. How this is calculated
SEA → MIA arrives on time 78.2% of the time; the return trip, MIA → SEA, arrives on time 68.2% of the time, a 10.0-point gap between the two directions of the same city pair.
SEA → MIA spends 31.9 minutes on the ground on a 2,724-mile trip: 22.7 minutes from pushback to wheels-up at SEA and 9.2 minutes from touchdown to gate at MIA.
Source: US DOT Bureau of Transportation Statistics · Data covering July 2023 – July 2026
What stands out
Unlike most, it barely matters what time you fly this route, a steadier spread than 99% of 4,023 comparable routes.
79.1% on time for 6–9 PM departures, against 75.4% for 12–3 PM, a narrow gap either way.
Source: FlyerIntel analysis of US DOT BTS data · July 2023 – July 2026 · Ranked against every other route with the same kind of figure and at least 4,023 in the comparison.
What sets this route apart
Where SEA to MIA differs most from similar routes by hour, weekday, month and airline, July 2023 – July 2026.
SEA to MIA is at its best against routes of similar length for flights scheduled at 8 PM: 79.1% arrive on time, 7.3 points ahead of the 71.8% those routes manage at that hour. Against all other routes the gap is 11.7 points.
SEA to MIA struggles most at 10 PM: 75.6% of its flights scheduled then arrive on time, 6.6 points behind the 82.2% on routes of similar length at the same hour.
In August, SEA to MIA runs 14.6 points below routes of similar length, 62.3% on time to 76.9%. Against all other routes the gap is 14.2 points.
October is kinder to SEA to MIA than to routes of similar length: 89.1% on time against 82.5%, 6.6 points better. Against all other routes the gap is 6.1 points.
SEA to MIA against comparable routes
July 2023 – July 2026| Measure | This route | Compared with | Them | Gap | Flights behind it |
|---|---|---|---|---|---|
| Hour: 8 PM departures | 79.1% | routes of similar length | 71.8% | +7.3 pts | 397 here, 25,908 there |
| Hour: 10 PM departures | 75.6% | routes of similar length | 82.2% | −6.6 pts | 611 here, 37,005 there |
| Month: August | 62.3% | routes of similar length | 76.9% | −14.6 pts | 212 here, 60,924 there |
| Month: October | 89.1% | routes of similar length | 82.5% | +6.6 pts | 211 here, 57,167 there |
Each comparison pools the flights of other routes, with this route’s own left out. Similar length means within 15% of this route’s 2,724 miles, with at least 5 such routes. A bucket is set against the most comparable group that has enough flights: similar length, then the same origin (at least 3 routes), then all other routes. Hours, weekdays and months appear only where both sides have 120 completed flights, and airlines where both have 600. The gap must be at least 2 points and 2 standard errors, and only the largest gap each way is kept per measure. These are differences in the flights counted, not causes.
When it goes wrong
July 2023 – July 2026
37 min late
against a median of 7 min early
Percentiles over 3,023 operations; cancelled and diverted flights are counted separately.
Will your connection be tight enough?
Layovers at MIA after arriving from SEA.
| Connection time | Chance of missing | Reads as |
|---|---|---|
| 30 min | 37% | Likely to miss |
| 45 min | 21% | High risk |
| 60 min | 13% | Some risk |
| 90 min | 5.8% | Some risk |
| 120 min | 3.0% | Low 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 0.99% of the time and diverts 0.46% of the time, which a late arrival never shows up in.
Chance of missing is the share of 2,979 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 37 minutes late (90th-percentile gate arrival delay), over 3,023 operations.
Any other layover length: connection checker.
Best time to fly
SEA → MIA flights departing 6–9 PM arrived on time 79.1% of the time, against 75.4% for 12–3 PM departures, a gap of 3.7 percentage points.
By departure window
By departure hour
- 12 AM to 6 AM: too few flights to score
- 7 AM: 78.8% on time from 950 flights
- 8 AM: 77.4% on time from 765 flights
- 9 AM to 7 PM: too few flights to score
- 8 PM: 79.1% on time from 399 flights
- 9 PM: too few flights to score
- 10 PM: 75.6% on time from 613 flights
- 11 PM: too few flights to score
Departure windows with fewer than 120 flights are not scored.
Why SEA → MIA runs late
July 2023 – July 2026
crew, maintenance, boarding and fueling, all within the carrier’s control
airspace and airport capacity, including weather-driven flow control
the inbound aircraft was late, so this flight started late
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 SEA → MIA. 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 | 1,252 | 78.4% | 0.64% | -8 min | 7.1% |
| Alaska Airlines | 1,181 | 77.3% | 1.35% | -6 min | 5.2% |
| Delta Air Lines | 590 | 79.5% | 1.02% | -8 min | 4.6% |
American Airlines flew 41.4% of the 3,023 flights listed.
Delta Air Lines arrived on time 2.2 percentage points more often than Alaska Airlines 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 |
|---|---|---|---|
| AA1471 American Airlines | 10:17 PM | 615 | 76.4% |
Weekly and seasonal patterns
By day of week
Tuesday is historically the most reliable day and Saturday the least, a gap of 8.1 percentage points.
By month
- Jan: 73.8%
- Feb: 82.2%
- Mar: 77.6%
- Apr: 82.0%
- May: 82.6%
- Jun: 79.0%
- Jul: 76.6%
- Aug: 62.3%
- Sep: 78.8%
- Oct: 89.1%
- Nov: 80.7%
- Dec: 74.7%
August is historically the weakest month and October the strongest, a spread of 26.8 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 (69)
- December 2024: too few flights to score (103)
- January 2025: too few flights to score (102)
- 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 (92)
- 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 (97)
- December 2025: 77.3% from 120 flights
- January 2026: too few flights to score (102)
- 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: 79.8% from 120 flights
- July 2026: 81.8% from 124 flights
Over the most recent 12 months (2025-08 to 2026-07), on-time arrivals averaged 78.4% against 79.3% in the 12 months before — broadly unchanged.
Data and methodology
Calculated by FlyerIntel from 3,023 SEA → MIA 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