How delayed is Ontario, CA (ONT)?

Ontario, CA has an on-time rate of 83.5%. The average delay is 11.3 min.

What causes delays at ONT?

The main delay causes at ONT are carrier issues (34.1%), weather (3.2%), NAS/air traffic control (18.5%), and late arriving aircraft (44.1%).

What is the best time to fly from ONT?

The best time to fly from ONT is at 5:00 with a 93.2% on-time rate. Nov is the best month with 86.6% on-time flights.

Ontario, CA

Ontario, CA, CA — ONT

On-Time Rate

83.5%

2019-2025

Avg Delay

11.3 min

when delayed

Cancel Rate

1.8%

flights cancelled

Total Flights

155,415

2019-2025

Best Month

Nov

86.6% on-time

Worst Month

Jun

80.3% on-time

Best Departure Time

5:00

93.2% on-time

12-Month On-Time Trend

Delay Causes

Best Time to Fly (By Hour)

Seasonal Pattern

Airlines at ONT

Airline	Flights	On-Time
Southwest Airlines	71,269	84.5%
American Airlines	19,825	81.7%
SkyWest Airlines	17,578	85.9%
Frontier Airlines	12,853	73.7%
Delta Air Lines	10,416	89.6%
Alaska Airlines	9,338	84.0%
United Airlines	7,579	84.0%
Mesa Airlines	2,722	84.1%
JetBlue Airways	1,743	70.9%
Hawaiian Airlines	1,532	81.0%

Most Delayed Routes

Destination	On-Time
ONT → MCOOrlando, FL	65.3%
ONT → JFKNew York, NY	70.9%
ONT → SFOSan Francisco, CA	77.7%
ONT → LASLas Vegas, NV	78.4%
ONT → ORDChicago, IL	78.8%

Most Punctual Routes

Destination	On-Time
ONT → SLCSalt Lake City, UT	91.1%
ONT → ATLAtlanta, GA	88.2%
ONT → PDXPortland, OR	87.8%
ONT → MDWChicago, IL	87.4%
ONT → BNANashville, TN	87.2%

Was your flight from Ontario, CA delayed?

You may be entitled to compensation of up to $700 per passenger for delayed or cancelled flights. Check your eligibility now.

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Data source: Bureau of Transportation Statistics (BTS) On-Time Performance dataset. Statistics are based on reported flight data from 2019-2025. See our data methodology for details.