ONT (Ontario) to ORD (Chicago) flights arrive on time 82% of the time. The most reliable airline on this route is United Airlines at 82%. The average delay is 67 minutes. Delays on this route are most often caused by the airline (crew, maintenance, or boarding).
Source: Bureau of Transportation Statistics. Updated October 2026.ONT → ORD
ONT (Ontario) to ORD (Chicago)
ONT → ORD on-time performance by month
25
26
JanFebMarAprMayJunJulAugSepOctNovDec
Worse
Better
This route is on time most of the time. About 82% of flights arrive on schedule.
Delays on this route are most often caused by the airline (crew, maintenance, or boarding).
Accurate?
Accurate?
Good to know
Departing from ONT
81% on timeTSA is currently ~14 min. Best time: 4 AM (about 5 min).
Arriving at ORD
77% on timeWhen flights into ORD are late, the average delay is 79 minutes. Build buffer if you have ground plans.
If connecting at ORD: TSA is ~36 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 ONT? We'll brief you.
Delays, TSA, weather, gates — we'll let you know if something matters.
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Data last updated October 2026. Source: Bureau of Transportation Statistics.