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

Houston, TX (IAH) to Ontario, CA (ONT) flight delay odds

75.5% of 538 official scheduled IAH-to-ONT flights arrived on time; 16.0% arrived at least 30 minutes late and 0.2% 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
75.5%arrived on time
16.0%30+ min late
0.2%cancelled
538scheduled flights
Based on July 2025–June 2026; on time means arrival less than 15 minutes late.
60+ minutes late8.7%all scheduled flights
120+ minutes late3.3%all scheduled flights
Diverted0.2%did not reach as scheduled
Average arrival+6.3 mincompleted flights

Which departure time was most reliable for IAH to ONT?

Among qualifying IAH-to-ONT departure window results, Evening had the highest on-time rate: 74.9% of 411 flights. Afternoon was lowest at 70.0% across 80 flights.

Departure windowFlightsOn time30+ minCancelled
Afternoon8070.0%16.2%0.0%
Evening41174.9%17.0%0.2%

Which weekday was most reliable for IAH to ONT?

Among qualifying IAH-to-ONT weekday results, Tuesday had the highest on-time rate: 85.7% of 63 flights. Monday was lowest at 69.1% across 97 flights.

DayFlightsOn time30+ minCancelled
Monday9769.1%22.7%1.0%
Tuesday6385.7%7.9%0.0%
Wednesday6373.0%17.5%0.0%
Thursday7475.7%14.9%0.0%
Friday10273.5%19.6%0.0%
Saturday6078.3%15.0%0.0%
Sunday7977.2%10.1%0.0%

Which airline was most reliable for IAH to ONT?

Among qualifying IAH-to-ONT airline results, United Airlines had the highest on-time rate: 77.5% of 365 flights. Frontier Airlines was lowest at 71.1% across 173 flights.

AirlineFlightsOn time30+ minCancelled
United Airlines36577.5%15.6%0.0%
Frontier Airlines17371.1%16.8%0.6%

Which month was most reliable for IAH to ONT?

Among qualifying IAH-to-ONT month results, February 2026 had the highest on-time rate: 91.7% of 36 flights. July 2025 was lowest at 56.4% across 39 flights.

MonthFlightsOn time30+ minCancelled
July 20253956.4%35.9%0.0%
August 20254060.0%20.0%2.5%
September 20254381.4%14.0%0.0%
October 20254868.8%10.4%0.0%
November 20254768.1%21.3%0.0%
December 20254470.5%11.4%0.0%
January 20264190.2%4.9%0.0%
February 20263691.7%8.3%0.0%
March 20264080.0%15.0%0.0%
April 20263984.6%15.4%0.0%
May 20266185.2%9.8%0.0%
June 20266070.0%25.0%0.0%

What drove IAH to ONT delay minutes?

Late aircraft was the largest recorded IAH-to-ONT delay category, accounting for 58.0% of 8,138 BTS-attributed delay minutes during July 2025–June 2026.

Airline30.3%
Late aircraft58.0%
National airspace9.1%
Weather2.6%
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.