Route on-time record
SEA to MIA: most on-time flights and the best time to fly
Seattle (Seattle–Tacoma International Airport) to Miami (Miami International Airport). 1,149 nonstop flights in Jun 2025 to May 2026, 77% arrived within 15 minutes and 1.0% were cancelled. The most reliable flight number was Delta 506 at 8:00 AM.
Flying on a specific date? We’ll adjust for the month, the weekday and the forecast.
SEA → MIA
Seattle to Miami: 1,149 nonstop flights a year
On time (12 months)
77%
Cancelled
1.0%
avg delay 12 min
Best time to leave
No clear winner
Most reliable airline
Delta
77% chance on time
Lowest nonstop fare seen in the next two months: $228 (American 2142 on 2026-11-14). Fares open on our travel partner (Aviasales). Pick the flight number you chose here.
Most reliable nonstop flights
Ranked by the chance the flight operates and arrives within 15 minutes of schedule, from Jun 2025 to May 2026 records.
#1 · Delta 506
8:00 AM → 4:46 PM5h 56m nonstop
Local times, typical schedule. Last flown 2026-05-31.
77%
chance on time
- On time (history)
- 78%
- Cancelled
- 1.4%
- Avg arrival delay
- 13 min
- Arrived on time 78% of the time (358 flights, Jun 2025 to May 2026).
- Departs outside SEA's trouble window (4 PM to 10 PM, when 54% of its 68 ground stops and delay programs started).
- Lands inside MIA's trouble window: 49% of its 45 ground stops and delay programs started between 1 PM and 7 PM.
Strong track record · 358 flights
Find Delta 506 fares Opens this date on Aviasales#2 · Alaska 305
8:05 AM → 5:04 PM6h 05m nonstop
Local times, typical schedule. Last flown 2026-05-31.
74%
chance on time
- On time (history)
- 74%
- Cancelled
- 0.4%
- Avg arrival delay
- 11 min
- Arrived on time 74% of the time (237 flights, Jun 2025 to May 2026).
- Departs outside SEA's trouble window (4 PM to 10 PM, when 54% of its 68 ground stops and delay programs started).
- Lands inside MIA's trouble window: 49% of its 45 ground stops and delay programs started between 1 PM and 7 PM.
Strong track record · 237 flights
Find Alaska 305 fares Opens this date on Aviasales#3 · American 1471
10:16 PM → 7:00 AM5h 44m nonstop
Local times, typical schedule. Last flown 2026-05-31.
73%
chance on time
- On time (history)
- 73%
- Cancelled
- 0.0%
- Avg arrival delay
- 14 min
- Arrived on time 73% of the time (207 flights, Jun 2025 to May 2026).
- Never cancelled in 207 scheduled flights.
- Departs outside SEA's trouble window (4 PM to 10 PM, when 54% of its 68 ground stops and delay programs started).
- 57% of its delay minutes came from the plane arriving late from an earlier flight.
Strong track record · 207 flights
Find American 1471 fares Opens this date on Aviasales#4 · American 654
1:03 PM → 9:52 PM5h 49m nonstop
Local times, typical schedule. Last flown 2026-05-31.
68%
chance on time
- On time (history)
- 55%
- Cancelled
- 0.0%
- Avg arrival delay
- 24 min
- Arrived on time 55% of the time (11 flights, Jun 2025 to May 2026).
- Departs outside SEA's trouble window (4 PM to 10 PM, when 54% of its 68 ground stops and delay programs started).
Limited track record · 11 flights
Find American 654 fares Opens this date on Aviasales
Airlines on this route
Season-adjusted chance of operating and arriving on time.
- Delta Air Lines77%
365 flights · 78% on time as flown · 1.2% cancel
- Alaska Airlines76%
391 flights · 77% on time as flown · 0.8% cancel
- American Airlines75%
393 flights · 75% on time as flown · 0.8% cancel
On time by departure time
All airlines, scheduled local departure, Jun 2025 to May 2026.
- Before 9 AM78%
728 flights · avg delay 11 min
- 6 to 9 PM76%
160 flights · avg delay 13 min
- After 9 PM75%
231 flights · avg delay 15 min
Best day: Tuesday (82%). Worst: Friday (73%).
On time by month
All airlines, Jun 2023 to May 2026. Several years per month, so one stormy season doesn't define a month. Travel-month estimates use this seasonal pattern.
What delays this route
- Airline (crew, maintenance, boarding)40%
- Air traffic control and airport volume36%
- Late-arriving aircraft21%
- Severe weather2%
Share of delay minutes by the cause airlines report to the US DOT.
Historical odds, not a guarantee. Built from the US DOT Bureau of Transportation Statistics on-time reports (Jun 2025 to May 2026), FAA ground stop and delay program advisories, and 20 years of airport weather observations. Covers US airlines that report to the DOT; schedules are flights operated recently, so confirm times when you book. ATIS Alerts is not affiliated with any airline. Fares are what Aviasales travelers saw in recent searches (USD, one way, 1 adult), not live quotes; the partner site shows the current price. Fare links go to our travel partner and may earn us a commission at no cost to you. Affiliate disclosure
SEA to MIA questions
- Which airline is most on time from SEA to MIA?
- Delta, with a season-adjusted 77% chance of operating and arriving on time over 365 flights. The adjustment compares each airline with what the route did in the months it flew, so a carrier that skipped a stormy month gets no free credit.
- What is the worst month for delays on SEA to MIA?
- August (62% on time); the best was October (89%), averaged over Jun 2023 to May 2026.
- Is this a prediction for my flight?
- No. These are historical odds from the US DOT on-time reports, FAA advisories and airport weather records. Check your flight status and the FAA delay board on the day you fly.
More routes from SEA
- MIA to SEA (return)
- SEA to LAX 83%
- SEA to PHX 79%
- SEA to SFO 69%
- SEA to ANC 74%
- SEA to DEN 77%
- SEA to LAS 77%
- SEA to ORD 75%
- SEA to GEG 81%
- SEA to DFW 77%
- SEA to PDX 82%
- SEA to SAN 78%
- SEA to SMF 81%
Most on-time flights from SEA on every route →
Live status: FAA delays and ground stops