BTS DATA COMPLETE THROUGH JUNE 2026HISTORICAL ODDS · NOT LIVE FLIGHT STATUS
DelayOddsKnow the route before you book
ONT→SFO

Ontario, CA (ONT) to San Francisco, CA (SFO) flight delay odds

64.4% of 1,290 official scheduled ONT-to-SFO flights arrived on time; 25.1% arrived at least 30 minutes late and 0.8% were cancelled during July 2025–June 2026.

Source: U.S. Bureau of Transportation Statistics · Reporting window: July 2025–June 2026 · Updated September 16, 2026

HISTORICAL ROUTE SIGNALVariable
64.4%arrived on time
25.1%30+ min late
0.8%cancelled
1,290scheduled flights
Based on July 2025–June 2026; on time means arrival less than 15 minutes late.
60+ minutes late12.4%all scheduled flights
120+ minutes late4.5%all scheduled flights
Diverted0.0%did not reach as scheduled
Average arrival+17.6 mincompleted flights

Which departure time was most reliable for ONT to SFO?

Among qualifying ONT-to-SFO departure window results, Early morning had the highest on-time rate: 85.9% of 348 flights. Evening was lowest at 44.7% across 380 flights.

Departure windowFlightsOn time30+ minCancelled
Early morning34885.9%7.2%1.1%
Late morning11145.0%43.2%0.0%
Afternoon34373.2%15.7%0.0%
Evening38044.7%42.4%0.8%
Night10856.5%33.3%2.8%

Which weekday was most reliable for ONT to SFO?

Among qualifying ONT-to-SFO weekday results, Tuesday had the highest on-time rate: 74.4% of 160 flights. Monday was lowest at 57.6% across 205 flights.

DayFlightsOn time30+ minCancelled
Monday20557.6%28.8%0.5%
Tuesday16074.4%16.2%0.6%
Wednesday15563.2%27.1%0.0%
Thursday19160.7%26.2%1.6%
Friday20763.8%28.5%0.5%
Saturday16374.2%17.2%0.6%
Sunday20960.8%28.7%1.4%

Which airline was most reliable for ONT to SFO?

Among qualifying ONT-to-SFO airline results, United Airlines had the highest on-time rate: 70.4% of 1,007 flights. Frontier Airlines was lowest at 40.7% across 177 flights.

AirlineFlightsOn time30+ minCancelled
United Airlines1,00770.4%19.4%0.4%
Frontier Airlines17740.7%48.6%2.3%
SkyWest Airlines10647.2%40.6%1.9%

Which month was most reliable for ONT to SFO?

Among qualifying ONT-to-SFO month results, March 2026 had the highest on-time rate: 89.3% of 103 flights. June 2026 was lowest at 33.3% across 120 flights.

MonthFlightsOn time30+ minCancelled
July 202510475.0%15.4%0.0%
August 202510970.6%19.3%0.9%
September 202510864.8%22.2%0.0%
October 202511457.9%24.6%0.0%
November 202510574.3%19.0%1.9%
December 202510474.0%17.3%1.9%
January 20269381.7%15.1%1.1%
February 20267972.2%20.3%0.0%
March 202610389.3%5.8%1.9%
April 202612453.2%34.7%0.0%
May 202612742.5%46.5%1.6%
June 202612033.3%49.2%0.0%

What drove ONT to SFO delay minutes?

National airspace was the largest recorded ONT-to-SFO delay category, accounting for 56.6% of 30,250 BTS-attributed delay minutes during July 2025–June 2026.

Airline15.3%
Late aircraft25.4%
National airspace56.6%
Weather2.7%
Security0.0%
This is historical evidence, not a forecast.

Weather, schedules and operations change. For a trip you have already booked, use the airline or airport for live status.