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

Ontario, CA (ONT) to Atlanta, GA (ATL) flight delay odds

87.9% of 937 official scheduled ONT-to-ATL flights arrived on time; 6.2% arrived at least 30 minutes late and 1.8% 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 SIGNALGenerally reliable
87.9%arrived on time
6.2%30+ min late
1.8%cancelled
937scheduled flights
Based on July 2025–June 2026; on time means arrival less than 15 minutes late.
60+ minutes late4.2%all scheduled flights
120+ minutes late1.9%all scheduled flights
Diverted0.7%did not reach as scheduled
Average arrival-2.4 mincompleted flights

Which departure time was most reliable for ONT to ATL?

Among qualifying ONT-to-ATL departure window results, Early morning had the highest on-time rate: 91.7% of 266 flights. Afternoon was lowest at 79.4% across 189 flights.

Departure windowFlightsOn time30+ minCancelled
Early morning26691.7%4.1%1.9%
Late morning17687.5%5.7%1.7%
Afternoon18979.4%11.1%1.6%
Night30690.2%5.2%2.0%

Which weekday was most reliable for ONT to ATL?

Among qualifying ONT-to-ATL weekday results, Wednesday had the highest on-time rate: 93.2% of 133 flights. Sunday was lowest at 84.3% across 140 flights.

DayFlightsOn time30+ minCancelled
Monday13886.2%6.5%1.4%
Tuesday13791.2%5.8%0.7%
Wednesday13393.2%3.0%0.0%
Thursday13689.0%6.6%1.5%
Friday13786.9%5.8%2.9%
Saturday11684.5%7.8%3.4%
Sunday14084.3%7.9%2.9%

Which airline was most reliable for ONT to ATL?

Only Delta Air Lines met the ONT-to-ATL airline threshold: 87.9% of 937 scheduled flights arrived on time during July 2025–June 2026.

AirlineFlightsOn time30+ minCancelled
Delta Air Lines93787.9%6.2%1.8%

Which month was most reliable for ONT to ATL?

Among qualifying ONT-to-ATL month results, September 2025 had the highest on-time rate: 97.4% of 77 flights. January 2026 was lowest at 72.3% across 65 flights.

MonthFlightsOn time30+ minCancelled
July 20258889.8%4.5%1.1%
August 20258295.1%1.2%1.2%
September 20257797.4%1.3%0.0%
October 20258588.2%7.1%0.0%
November 20258486.9%7.1%2.4%
December 20258885.2%6.8%4.5%
January 20266572.3%16.9%6.2%
February 20265692.9%0.0%0.0%
March 20266279.0%6.5%3.2%
April 20267790.9%7.8%0.0%
May 20269386.0%9.7%1.1%
June 20268088.8%5.0%2.5%

What drove ONT to ATL delay minutes?

Airline was the largest recorded ONT-to-ATL delay category, accounting for 63.3% of 8,836 BTS-attributed delay minutes during July 2025–June 2026.

Airline63.3%
Late aircraft28.4%
National airspace6.4%
Weather0.0%
Security1.8%
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.