SFO (San Francisco) to ONT (Ontario) flights arrive on time 81% of the time. The most reliable airline on this route is United Airlines at 83%. The average delay is 72 minutes. Delays on this route are most often caused by the incoming plane arriving late.
Source: Bureau of Transportation Statistics. Updated August 2026.SFO → ONT
SFO (San Francisco) to ONT (Ontario)
SFO → ONT on-time performance by month
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JanFebMarAprMayJunJulAugSepOctNovDec
Worse
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This route is on time most of the time. About 81% of flights arrive on schedule.
Delays on this route are most often caused by the incoming plane arriving late.
Accurate?
United Airlines edges out Frontier Airlines on this route — 83% vs 69% on time.
Airline Comparison
United Airlines leads at 83% on time; Frontier Airlines trails at 69%.
Accurate?
Good to know
Departing from SFO
78% on timeExpect ~21 min sitting on the taxiway after your gate pushes back. SFO has long runway queues.
TSA is currently ~20 min. Best time: 4 AM (about 5 min).
Arriving at ONT
82% on timeWhen flights into ONT are late, the average delay is 64 minutes. Build buffer if you have ground plans.
If connecting at ONT: TSA is ~27 min right now. Allow at least 60 minutes for a domestic connection.
Flight cancelled or delayed?
Check what United Airlines owes you — refund rights, action plan, complaint email. Free.
Flying out of SFO? We'll brief you.
Delays, TSA, weather, gates — we'll let you know if something matters.
Know someone flying soon?
Send them the link — delay data, TSA waits, weather, all free.
Data last updated August 2026. Source: Bureau of Transportation Statistics.