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

Denver, CO (DEN) to Ontario, CA (ONT) flight delay odds

73.3% of 2,671 official scheduled DEN-to-ONT flights arrived on time; 16.8% arrived at least 30 minutes late and 0.1% 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
73.3%arrived on time
16.8%30+ min late
0.1%cancelled
2,671scheduled flights
Based on July 2025–June 2026; on time means arrival less than 15 minutes late.
60+ minutes late8.3%all scheduled flights
120+ minutes late2.7%all scheduled flights
Diverted0.0%did not reach as scheduled
Average arrival+9.8 mincompleted flights

Which departure time was most reliable for DEN to ONT?

Among qualifying DEN-to-ONT departure window results, Early morning had the highest on-time rate: 89.3% of 507 flights. Night was lowest at 61.2% across 508 flights.

Departure windowFlightsOn time30+ minCancelled
Early morning50789.3%4.3%0.0%
Late morning47984.6%9.0%0.0%
Afternoon41572.5%14.7%0.2%
Evening76264.0%25.2%0.1%
Night50861.2%25.8%0.4%

Which weekday was most reliable for DEN to ONT?

Among qualifying DEN-to-ONT weekday results, Wednesday had the highest on-time rate: 78.9% of 355 flights. Monday was lowest at 66.5% across 406 flights.

DayFlightsOn time30+ minCancelled
Monday40666.5%19.5%0.0%
Tuesday35676.7%15.7%0.3%
Wednesday35578.9%15.2%0.0%
Thursday40870.8%20.1%0.2%
Friday40774.0%14.7%0.2%
Saturday33475.7%15.6%0.3%
Sunday40572.1%16.3%0.0%

Which airline was most reliable for DEN to ONT?

Among qualifying DEN-to-ONT airline results, Frontier Airlines had the highest on-time rate: 78.8% of 551 flights. Southwest Airlines was lowest at 67.9% across 1,267 flights.

AirlineFlightsOn time30+ minCancelled
Southwest Airlines1,26767.9%19.2%0.2%
United Airlines85377.8%14.7%0.0%
Frontier Airlines55178.8%14.7%0.4%

Which month was most reliable for DEN to ONT?

Among qualifying DEN-to-ONT month results, November 2025 had the highest on-time rate: 83.2% of 220 flights. June 2026 was lowest at 55.6% across 250 flights.

MonthFlightsOn time30+ minCancelled
July 202527258.1%32.0%0.7%
August 202525470.9%18.9%0.0%
September 202523675.8%11.4%0.0%
October 202524273.6%12.8%0.4%
November 202522083.2%9.1%0.5%
December 202519469.1%21.6%0.0%
January 202618582.7%11.9%0.0%
February 202617182.5%11.1%0.0%
March 202620083.0%11.0%0.0%
April 202620581.5%9.8%0.0%
May 202624274.4%16.1%0.0%
June 202625055.6%28.8%0.0%

What drove DEN to ONT delay minutes?

Late aircraft was the largest recorded DEN-to-ONT delay category, accounting for 55.5% of 39,709 BTS-attributed delay minutes during July 2025–June 2026.

Airline34.3%
Late aircraft55.5%
National airspace9.3%
Weather1.0%
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.