Ontario to San Francisco

What the Data Says About ONT to SFO

The Ontario to San Francisco corridor (ONT → SFO) covers roughly 363 miles and is served by 12 carriers, based on Bureau of Transportation Statistics reporting. Across 8,435 flights in the dataset, this route posts a 81.5% on-time rate with an average delay of 75.4 minutes when flights run late. Over the most recent 24 months of BTS data, 2,841 flights were recorded on this pairing — 35 cancelled (1.2%) and 2 diverted (0.1%). Those baseline metrics tell you what to expect before you book.

Having 12 carriers on the route matters: more carriers generally means more daily schedule options, competitive pricing, and redundancy when flights are cancelled. With 8,435 total flights analyzed, the 81.5% on-time figure is statistically meaningful rather than a small-sample fluke. The 75.4-minute average delay applies only to flights that actually ran late, so it is not the average wait across all departures — the majority of flights on this route depart on time under the BTS definition of a delay (15+ minutes past schedule).

Looking at recent months, Jan 2025 posted the best performance on this corridor at 91% on-time, while May 2024 came in at 48% on-time — a 43-point gap between best and worst recent month. For travelers evaluating the ONT to SFO route, the combination of a 81.5% on-time rate, 75.4-minute average delay, 1.2% recent cancellation rate, and 12 available carriers is the concrete summary of what BTS data shows about reliability on this pairing.