Airport month record

ONTOCT

Ontario International in October 2025

Departures: 2,265
Month: October 2025
National, same month: 79.7%
Carriers: 7

Historical statistics for October 2025, not live status or a forecast for this year’s October. For today’s conditions at ONT, see live FAA status.

ONT in October lands a B+, 2 points better than the national rate of 79.7%. Roughly one flight in five arrives 15 minutes late or worse, and those flights are late by about an hour on average. That rests on 2,265 flights, with a median arrival 6 minutes early.

On time

81.6%

Arrivals under 15 minutes late, of 2,251 completed departures

Avg delay

64 min

Across delayed arrivals only, not all flights

Cancelled

0.49%

Nationally in October: 0.53%

Whole year

81.9%

ONT across all twelve months

These figures cover 2,265 departures from Ontario International in October 2025. On time means an arrival less than 15 minutes after the scheduled gate time, the DOT's threshold, and the national comparison uses every US departure in the same month rather than the whole year.

Against the year

October next to ONT's other months

Against ONT's own year, October ran level with the twelve-month rate of 81.9%, which makes it number eight of twelve months, best first. Cancellations were unusually low for ONT in October, at 0.49% against 0.87% across the year. Either side of it, September ran 84.8% on time and November 81.9%, so this month sits in line with its neighbours.

ONT month by month
Month	Flights	On time	Avg delay	Cancelled	Grade
September 2025	2,177	84.8%	76 min	0.51%	B+
October 2025 (this page)	2,265	81.6%	64 min	0.49%	B+
November 2025	2,184	81.9%	63 min	2.06%	B
December 2025	2,132	82.4%	70 min	0.70%	B+
January 2026	1,892	86.5%	87 min	1.69%	A
February 2026	1,734	87.8%	70 min	0.35%	A+
March 2026	2,081	82.8%	57 min	1.01%	B
April 2026	2,119	82.8%	61 min	0.28%	B+
May 2026	2,298	80.0%	58 min	0.70%	B+
June 2026	2,304	76.7%	66 min	1.00%	B
July 2026	2,377	77.9%	75 min	0.88%	B+
August 2026	2,228	80.9%	70 min	0.81%	B+

Departure window

The best time of day to leave ONT in October

Departure time matters more here than the choice of carrier. The gap between the best and worst window is 23 points, against half a point between the best and worst carrier.

5am–8am591 flights92.2%
8am–11am371 flights87.0%
11am–2pm463 flights81.7%
2pm–5pm336 flights71.0%
5pm–8pm267 flights69.3%
8pm–5am237 flights75.1%

Scale runs 60% to 100%.

Book the early departure. Flights leaving between 5am–8am arrive on time 92.2% of the time, against 69.3% for the evening window. That is 23 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 5am–8am window is the busiest, with 591 flights scheduled in it.

Across the week, Saturday is the strongest day at 89.1% on time and Sunday the weakest at 75.7%, a spread of 13 points.

Carrier by carrier

Which airlines ran best at ONT in October

Only one carrier clears this site's 365-flight floor here, so there is no comparison to draw. The table below is the full picture.

Carriers at ONT in October 2025
Airline	Flights	On time	Avg delay	Cancelled	Grade
Southwest Airlines	1,003	80.2%	49 min	0.20%	B+
American Airlinesthin sample	337	80.8%	96 min	0.59%	B+
United Airlinesthin sample	238	76.4%	53 min	0.42%	B+
Frontier Airlinesthin sample	208	78.6%	73 min	0.96%	B+
SkyWest Airlinesthin sample	155	94.8%	82 min	0.00%	A+
Delta Air Linesthin sample	152	89.4%	116 min	0.00%	A+
Alaska Airlinesthin sample	147	83.2%	55 min	2.72%	B

Route by route

Busiest routes out of ONT in October

Routes from ONT in October 2025
Route	Flights	On time	Avg delay	Cancelled	Grade
ONT to PHX · Phoenixthin sample	258	76.7%	72 min	0.00%	B+
ONT to DEN · Denverthin sample	241	86.2%	89 min	0.83%	A+
ONT to LAS · Las Vegasthin sample	228	79.3%	54 min	0.44%	B+
ONT to DFW · Dallas-Fort Worththin sample	207	80.2%	79 min	1.45%	B
ONT to SEA · Seattlethin sample	200	84.8%	51 min	1.00%	B
ONT to SMF · Sacramentothin sample	181	81.8%	52 min	0.00%	B+
ONT to OAK · Oaklandthin sample	136	81.6%	57 min	0.00%	B+
ONT to SLC · Salt Lake Citythin sample	115	93.9%	78 min	0.00%	A+
ONT to SFO · San Franciscothin sample	114	57.9%	51 min	0.00%	D+
ONT to SJC · San Josethin sample	110	78.2%	39 min	0.00%	B+
ONT to ATL · Atlantathin sample	85	89.3%	146 min	0.00%	A+
ONT to IAH · Houstonthin sample	48	89.6%	126 min	0.00%	A+
ONT to PDX · Portlandthin sample	43	78.6%	71 min	2.33%	B
ONT to ORD · Chicagothin sample	31	71.0%	22 min	0.00%	C+
ONT to DAL · Dallasthin sample	31	86.7%	30 min	3.23%	A−
ONT to HNL · Honoluluthin sample	31	96.7%	17 min	3.23%	A−
ONT to BNA · Nashvillethin sample	31	87.1%	105 min	0.00%	A+
ONT to BWI · Baltimorethin sample	31	83.9%	36 min	0.00%	B+
ONT to MDW · Chicagothin sample	31	100.0%	—	0.00%	A+
ONT to CLT · Charlottethin sample	31	83.9%	33 min	0.00%	B+
ONT to HOU · Houstonthin sample	30	70.0%	79 min	0.00%	C+

Delay causes

What held ONT up in October

Carriers report a reason for every delay minute they cause, in five DOT categories. The split below is by minutes, not by number of flights, so a handful of very long weather delays weighs as much as many short ones. It covers 26,000 reported delay minutes.

Late-arriving aircraft
41%
Carrier
35%
National Airspace System
22%
Extreme weather
2%
Security
0%

41% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 26,000 reported delay minutes here, that single category outweighs weather by 25 to one. The split is drawn from 26,342 reported delay minutes.

Cancellations are rare at 0.49%, below the national 0.53% and low enough to earn the plus on the grade. Roughly one flight in 100 is called off; the risk here is arriving late, not not arriving.

5.2% of arrivals land an hour or more late, close to the national 6.3%, so a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last about an hour, which a normal layover absorbs.

What to do with this

Flying from ONT in October

For a October trip through ONT: expect 81.6% on time and 0.49% cancelled, going by October 2025. The 5am–8am window was the strongest part of the day.

Ontario International (ONT), the whole year
ONT in September84.8%
ONT in November81.9%
ONT in December82.4%
ONT in January86.5%
ONT in February87.8%
ONT in March82.8%
ONT in April82.8%
ONT in May80.0%
ONT in June76.7%
ONT in July77.9%
ONT in August80.9%

Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated 22 October 2026; recomputed monthly. How this data is collected.

Key figures