ONT → SEAOntario to Seattle

live

Direct flights from Ontario (ONT) to Seattle (SEA): 53 nonstop departures observed each week across 4 airlines. 50% of the last 8 tracked flights arrived within 15 minutes of schedule. The median arrival is 24 minutes early. 4 of the 21 tracked flights were cancelled. The nonstop covers 1,540 km, an estimated 2 hours 28 minutes in the air. Measured by Pro Flight Search from live flight boards at Ontario and Seattle. Updated 15 November 2026 at 12:05 UTC.

Today, ONT → SEA

Sun 15 Nov · local times
  1. · AS571Alaska On schedule SEA est. 18:38sched 18:56
  2. · AS575Alaska On schedule SEA est. 14:33sched 14:49
  3. · AS594Alaska On schedule SEA est. 21:43sched 22:00
  4. · AS607Alaska On schedule SEA 08:51scheduled
  5. · DL3816Delta Air Lines On schedule SEA est. 09:38sched 10:01
  6. · DL4031Delta Air Lines On schedule SEA est. 20:26sched 20:57
  7. · DL4070Delta Air Lines On schedule SEA est. 14:39sched 14:56
  8. · F92275Frontier On schedule SEA 20:08scheduled

Checked ONT board 22:18 · SEA board 04:05

ONT Ontario heavy · +45
SEA Seattle smooth · +8
1,540 km · ~2h 28m est.
dep bank 01:20–19:1353x weekly
Runs rough · 4 airlines · 53x weekly · nonstop
50% on time

of the last 8 tracked ONT → SEA flights arrived within 15 minutes

Median arrival delay is −24 min. 4 of 21 tracked legs cancelled in the sample. Will a delayed flight be cancelled? →

Median arrival−24 minacross the last 4 arrivals
Flight time~2h 28mestimated from route distance
Weekly departures53x4 direct airlines on the leg
Cancelled19.0%recent route rate · 4 of 21

The week

scheduled departures · origin local time
06121824
Mon
Tue
Wed
Thu
Fri
Sat
Sun
Alaska AirlinesDelta Air LinesFrontier AirlinesSouthwest Airlines

Each mark is a scheduled departure at its origin-local time, observed operating in the last 7 days. Today is highlighted.

Who flies it

observed on the boards · 7 days
Alaska AirlinesAS40% on time

Flights AS607 06:00 daily · AS575 12:02 daily · AS571 16:09 daily · AS594 19:13 Mo Th Fr Su

Delta Air LinesDL

Flights DL3816 varies daily · DL4070 11:57 Mo Tu We Th Fr Su · DL4031 varies daily

Frontier AirlinesF9

Flights F92275 17:06 Mo Th Fr Su

Southwest AirlinesWN

Flights WN3309 01:20 Mo Th Fr Su

History

operated legs · board outcomes
11-14AS571departed+61
11-14AS575cancelledCNX
11-14AS607departed+6
11-14DL3816departed−1
11-14DL4031departed+18
11-13AS571cancelledCNX
11-13AS575dep +9 → arr+8
11-13AS594cancelledCNX
11-13AS607dep +17 → arr−24
11-13DL3816dep +5 → arr−24
11-13DL4031departed+248
11-13DL4070dep +4 → arr−44
11-13F92275cancelledCNX
11-12AS571departed+18
11-12AS575departed+36
11-12AS594departed+55
11-12AS607departed+25
11-12DL3816departed+11
11-12DL4031departed+102
11-12DL4070departed+33
11-12F92275departed+5

Actual board outcomes rather than schedules, paired departure and arrival per flight and day.

Full board history, day by day →

Airports right now

live boards
ONTOntario +45 min heavy 🌤 few clouds · N 0 kt Full ONT delay board →
SEASeattle +8 min smooth 🌤 overcast · S 10 kt Full SEA delay board →

Weather lens

Conditions are tightest at ONT: a 37% chance of a 15+ minute delay. In this weather, the more delayed of the two airports is typically about +8 min. Both figures come from the two airports' delay records in similar weather. See live delays → · Weather risk by airport →

How the Ontario to Seattle route actually runs

Pro Flight Search records official board updates for nonstop ONT to SEA flights through the day: schedules, estimates, gate pushes and actual departures. The verdict above comes from operated flights, so it reflects what this route does rather than what the timetable promises.

Planning around a delay? Live airport delays · Weather delay risk map · Will a delayed flight be cancelled? · Do planes make up time in the air? · How we measure

Cite this data

Journalists, bloggers, and researchers may cite this page with attribution and a link to Pro Flight Search.

Suggested citation

Pro Flight Search: Ontario (ONT) to Seattle (SEA) route reliability, measured from operated flights on official airport boards.

Canonical URL
https://proflightsearch.com/search-flights/ONT-SEA
How we measure this →

ONT to SEA questions

Is ONT–SEA running on time right now?

Some delays possible. The departure side at ONT is the weaker end, route health score 64/100. The airports section above carries the live status and delay window at both ends.

Morning or evening flight on ONT–SEA?

Operators schedule morning departures around 06:00 and evening departures around 17:06 from ONT. Earlier flights typically land before destination-airport delays accumulate later in the day; check the SEA delay card to confirm conditions when you'd arrive.

How long is the flight from ONT to SEA?

Great-circle distance is 1,540 km. With typical jet cruise speed plus taxi, climb and descent, expect roughly 139–162 min gate-to-gate on this route.

How often does ONT–SEA fly?

4 carriers operate this route, around 53 flights a week between them. Compare carrier days and times in the airline list above.