Ontario International in July 2025

76.6%departed on time

BTS: A flight is counted as on time if it arrived less than 15 minutes after its scheduled time. Only carriers with at least 0.5 percent of domestic scheduled passenger revenue report.

In July 2025, reporting carriers scheduled 2,394 domestic departures from Ontario International (ONT). 76.6% left less than 15 minutes late and 77.4% reached their destination on time; 1.2% were cancelled.

Nationally that month, 69.7% of flights departed on time and 69.0% arrived on time, so ONT departures were 6.9 points above the national departure figure.

A year earlier, in July 2024, the airport had 2,410 departures with 79.0% leaving on time: a change of −2.4 points, with flights down 1%.

Flights arriving at ONT that month were on time 70.0% of the time (2,394 scheduled arrivals).

Of the delay minutes that carriers assigned to a BTS cause category that month, late-arriving aircraft 52%, air carrier 28% and national aviation system 20%.

On time 77.4%
Arrived 15+ minutes late 21.1%
Cancelled 1.2%
Diverted 0.3%

Every scheduled departure from ONT in July 2025, judged by arrival at the destination.

July 2025 against a year earlier, the airport's year and the nation

Measure	Jul 2025	Jul 2024	ONT, 12 months to Jul 2026	All reported flights, Jul 2025
Departed on time	76.6%	79.0%	80.3%	69.7%
Arrived on time	77.4%	79.5%	81.2%	69.0%
Cancelled	1.2%	2.2%	0.9%	2.5%
Average departure delay (late minutes only)	18.1 min	14.0 min	13.7 min	24.3 min
Scheduled departures a day	80	80	71	21,048
Scheduled departures	2,394	2,410	25,854	631,428

Airlines that month

Reporting carrier	Flights	Share	On time	Avg arrival delay	Cancelled
WN Southwest Airlines	1,038	43%	80.3%	7.8 min	0.4%
AA American Airlines	321	13%	67.3%	26.5 min	1.9%
UA United Airlines	241	10%	73.0%	12.8 min	0.0%
F9 Frontier Airlines	223	9%	68.6%	15.9 min	3.1%
OO SkyWest Airlines	184	8%	89.7%	-2.1 min	0.0%
AS Alaska Airlines	180	8%	73.3%	9.6 min	5.0%
DL Delta Air Lines	176	7%	90.3%	-9.0 min	0.6%
B6 JetBlue Airways	31	1%	61.3%	57.3 min	6.5%

Busiest routes that month

Route	Cities	Flights	On time	Avg arrival delay	Cancelled
ONT–SEA	Ontario to Seattle	302	79.1%	4.7 min	3.0%
ONT–DEN	Ontario to Denver	272	64.0%	23.1 min	1.1%
ONT–PHX	Ontario to Phoenix	263	81.4%	4.9 min	0.8%
ONT–DFW	Ontario to Dallas/Fort Worth	224	62.5%	29.8 min	4.5%
ONT–LAS	Ontario to Las Vegas	216	74.1%	15.5 min	0.9%
ONT–SMF	Ontario to Sacramento	178	86.5%	5.5 min	0.0%
ONT–OAK	Ontario to Oakland	135	88.1%	1.0 min	0.0%
ONT–SJC	Ontario to San Jose	118	77.1%	7.4 min	0.0%
ONT–SLC	Ontario to Salt Lake City	116	91.4%	-6.0 min	0.0%
ONT–SFO	Ontario to San Francisco	104	75.0%	7.0 min	0.0%
ONT–ATL	Ontario to Atlanta	88	89.8%	-11.5 min	1.1%
ONT–IAH	Ontario to Houston	38	81.6%	19.1 min	0.0%

By scheduled departure hour

On-time share:under 62%6270768288% and over

Share of departures that left less than 15 minutes late, by scheduled hour (local time), July 2025.

Delay causes

BTS cause category	Share of delay minutes	National, Jul 2025	Minutes
Air carrier	27.6%	31.1%	10,806
Late-arriving aircraft	51.8%	40.8%	20,267
National Aviation System	20.1%	20.7%	7,856
Extreme weather	0.5%	7.3%	211
Security	0.0%	0.1%	16

39,156 delay minutes on 505 flights that arrived 15 or more minutes late and carried a cause report. Carriers assign the categories; see what each category means.

Questions and answers

How many flights left ONT on time in July 2025?

76.6% of 2,394 scheduled domestic departures left less than 15 minutes late, and 77.4% reached their destination on time. The national figures that month were 69.7% and 69.0%.

How does that compare with a year earlier?

In July 2024, 79.0% of 2,410 departures left on time and 2.2% were cancelled, against 76.6% and 1.2% in July 2025.

Provenance

Source: Bureau of Transportation Statistics, Reporting Carrier On-Time Performance, file for July 2025; public domain. Domestic scheduled flights by reporting carriers, totals and averages only. The site's data runs through July 2026. Full record for ONT · methodology · corrections.