Ontario International in July 2026

76.8%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 2026, reporting carriers scheduled 2,377 domestic departures from Ontario International (ONT). 76.8% left less than 15 minutes late and 77.0% reached their destination on time; 0.9% were cancelled.

Nationally that month, 68.8% of flights departed on time and 69.4% arrived on time, so ONT departures were 8.0 points above the national departure figure.

A year earlier, in July 2025, the airport had 2,394 departures with 76.6% leaving on time: a change of +0.2 points, with flights down 1%.

Flights arriving at ONT that month were on time 71.5% of the time (2,375 scheduled arrivals).

Of the delay minutes that carriers assigned to a BTS cause category that month, air carrier 42%, late-arriving aircraft 38% and national aviation system 18%.

On time 77.0%
Arrived 15+ minutes late 21.8%
Cancelled 0.9%
Diverted 0.3%

Every scheduled departure from ONT in July 2026, judged by arrival at the destination.

July 2026 against a year earlier, the airport's year and the nation

Measure	Jul 2026	Jul 2025	ONT, 12 months to Jul 2026	All reported flights, Jul 2026
Departed on time	76.8%	76.6%	80.3%	68.8%
Arrived on time	77.0%	77.4%	81.2%	69.4%
Cancelled	0.9%	1.2%	0.9%	2.6%
Average departure delay (late minutes only)	18.3 min	18.1 min	13.7 min	24.1 min
Scheduled departures a day	79	80	71	21,066
Scheduled departures	2,377	2,394	25,854	631,970

Airlines that month

Reporting carrier	Flights	Share	On time	Avg arrival delay	Cancelled
WN Southwest Airlines	1,049	44%	78.1%	6.4 min	0.5%
AA American Airlines	302	13%	79.5%	23.7 min	1.0%
F9 Frontier Airlines	248	10%	70.2%	8.0 min	2.0%
AS Alaska Airlines	212	9%	77.8%	5.5 min	1.4%
UA United Airlines	185	8%	74.6%	7.2 min	1.1%
OO SkyWest Airlines	177	7%	76.3%	7.0 min	0.0%
DL Delta Air Lines	173	7%	85.5%	-2.0 min	0.6%
B6 JetBlue Airways	31	1%	35.5%	140.1 min	6.5%

Busiest routes that month

Route	Cities	Flights	On time	Avg arrival delay	Cancelled
ONT–SEA	Ontario to Seattle	256	79.7%	4.9 min	1.2%
ONT–DEN	Ontario to Denver	243	78.2%	10.7 min	0.0%
ONT–PHX	Ontario to Phoenix	231	78.4%	10.7 min	0.4%
ONT–DFW	Ontario to Dallas/Fort Worth	214	76.6%	26.1 min	0.9%
ONT–LAS	Ontario to Las Vegas	213	68.5%	9.2 min	1.9%
ONT–SMF	Ontario to Sacramento	183	84.2%	-0.1 min	1.1%
ONT–SFO	Ontario to San Francisco	123	43.9%	26.2 min	0.8%
ONT–SJC	Ontario to San Jose	119	81.5%	2.6 min	0.0%
ONT–OAK	Ontario to Oakland	116	91.4%	-1.9 min	0.0%
ONT–SLC	Ontario to Salt Lake City	116	90.5%	-3.2 min	0.0%
ONT–ATL	Ontario to Atlanta	88	77.3%	6.0 min	1.1%
ONT–HNL	Ontario to Honolulu	62	79.0%	5.9 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 2026.

Delay causes

BTS cause category	Share of delay minutes	National, Jul 2026	Minutes
Air carrier	42.3%	31.7%	16,338
Late-arriving aircraft	38.2%	41.8%	14,749
National Aviation System	18.0%	19.9%	6,954
Extreme weather	1.3%	6.5%	499
Security	0.2%	0.1%	67

38,607 delay minutes on 519 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 2026?

76.8% of 2,377 scheduled domestic departures left less than 15 minutes late, and 77.0% reached their destination on time. The national figures that month were 68.8% and 69.4%.

How does that compare with a year earlier?

In July 2025, 76.6% of 2,394 departures left on time and 1.2% were cancelled, against 76.8% and 0.9% in July 2026.

Provenance

Source: Bureau of Transportation Statistics, Reporting Carrier On-Time Performance, file for July 2026; 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.