Historical on-time performance
Seattle to Miami
2,724 miData through Dec 2025Source: US DOT · BTS
Flights on SEA–MIA arrive on time 78% of the time over the last 12 months.
On-time rate78%arrived within 15 min
p90 delay30 min1 in 10 flights is worse (tail risk)
Cancelled0.6%of scheduled flights
based on 1,053 flights over the last 12 months. On-time means arriving within 15 minutes (BTS standard).
By airline
How each carrier compares
Too close to call — no single carrier is clearly more on-time here.
- Delta Air LinesOn-time79%Medianon timep9025 minCancel0.9%Flights337
- American AirlinesOn-time78%Medianon timep9035 minCancel0.0%Flights354
- Alaska AirlinesOn-time78%Medianon timep9030 minCancel0.8%Flights362
Why flights run late
Delay causes
- Airline31%
- Weather2%
- Air traffic (NAS)36%
- Late aircraft32%
- Security0%
Most delay minutes here are attributed to Air traffic (NAS).
Over time
On-time trend
By season
On-time rate by month
When to fly
Best time to fly SEA → MIA
All airlines · rolling 36 months (2023-01 .. 2025-12).
Best time of day
On-time rates are fairly even by time of day on this route — ranging from 72% to 78% on time.
- Overnights78% on time · p90 45 min · 1,137 flights
- Mornings75% on time · p90 35 min · 1,476 flights
- Middays72% on time · p90 35 min · 50 flights · limited
Best day of week
On-time rates are fairly even by day on this route — ranging from 73% to 81% on time.
- Tuesdays81% on time · p90 35 min · 374 flights
- Sundays78% on time · p90 35 min · 390 flights
- Mondays77% on time · p90 40 min · 383 flights
- Thursdays76% on time · p90 35 min · 386 flights
- Saturdays75% on time · p90 45 min · 379 flights
- Wednesdays73% on time · p90 40 min · 380 flights
- Fridays73% on time · p90 35 min · 384 flights
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