Airport month record
ONTJUL
Ontario International in July 2026
- Departures
- 2,377
- Month
- July 2026
- National, same month
- 71.7%
- Carriers
- 8
Historical statistics for July 2026, not live status or a forecast for this year’s July. For today’s conditions at ONT, see live FAA status.
ONT in July lands a B+, 6 points better than the national rate of 71.7%. Roughly one flight in five arrives 15 minutes late or worse, and those flights are late by a little over an hour on average. That rests on 2,377 flights, with a median arrival 5 minutes early.
Set against the rest of the country, ONT's July record is 6 points better than the US average of 71.7%. That gap is worth roughly 62 fewer late arrivals for every thousand flights.
Key figures
On time
77.9%
Arrivals under 15 minutes late, of 2,349 completed departures
Avg delay
75 min
Across delayed arrivals only, not all flights
Cancelled
0.88%
Nationally in July: 2.62%
Whole year
81.9%
ONT across all twelve months
These figures cover 2,377 departures from Ontario International in July 2026. 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
July next to ONT's other months
Against ONT's own year, July ran 4 points worse than the twelve-month rate of 81.9%, which makes it number eleven of twelve months, best first. Either side of it, June ran 76.7% on time and August 80.9%, so this month sits in line with its neighbours.
| Month | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| September 2025 | 2,177 | 84.8% | 76 min | 0.51% | B+ |
| October 2025 | 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 (this page) | 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 July
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 29 points, against half a point between the best and worst carrier.
- 5am–8am568 flights93.1%
- 8am–11am430 flights80.5%
- 11am–2pm442 flights76.0%
- 2pm–5pm343 flights64.6%
- 5pm–8pm295 flights72.1%
- 8pm–5am299 flights69.2%
Scale runs 55% to 100%.
Book the early departure. Flights leaving between 5am–8am arrive on time 93.1% of the time, against 64.6% for the afternoon window. That is 29 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 568 flights scheduled in it.
Across the week, Saturday is the strongest day at 83.2% on time and Thursday the weakest at 74.2%, a spread of 9 points.
Carrier by carrier
Which airlines ran best at ONT in July
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.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Southwest Airlines | 1,049 | 78.4% | 54 min | 0.48% | B+ |
| American Airlinesthin sample | 302 | 80.5% | 169 min | 0.99% | B+ |
| Frontier Airlinesthin sample | 248 | 71.6% | 51 min | 2.02% | C |
| Alaska Airlinesthin sample | 212 | 78.9% | 50 min | 1.42% | B |
| United Airlinesthin sample | 185 | 75.8% | 54 min | 1.08% | B |
| SkyWest Airlinesthin sample | 177 | 76.3% | 75 min | 0.00% | B+ |
| Delta Air Linesthin sample | 173 | 88.6% | 75 min | 0.58% | A+ |
| JetBlue Airwaysthin sample | 31 | 37.9% | 231 min | 6.45% | F− |
Route by route
Busiest routes out of ONT in July
| Route | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| ONT to SEA · Seattlethin sample | 256 | 80.6% | 68 min | 1.17% | B |
| ONT to DEN · Denverthin sample | 243 | 78.2% | 76 min | 0.00% | B+ |
| ONT to PHX · Phoenixthin sample | 231 | 78.7% | 73 min | 0.43% | B+ |
| ONT to DFW · Dallas-Fort Worththin sample | 214 | 77.7% | 157 min | 0.93% | B+ |
| ONT to LAS · Las Vegasthin sample | 213 | 69.9% | 47 min | 1.88% | C |
| ONT to SMF · Sacramentothin sample | 183 | 85.1% | 60 min | 1.09% | A |
| ONT to SFO · San Franciscothin sample | 123 | 44.3% | 50 min | 0.81% | F+ |
| ONT to SJC · San Josethin sample | 119 | 81.5% | 63 min | 0.00% | B+ |
| ONT to OAK · Oaklandthin sample | 116 | 91.4% | 105 min | 0.00% | A+ |
| ONT to SLC · Salt Lake Citythin sample | 116 | 90.5% | 112 min | 0.00% | A+ |
| ONT to ATL · Atlantathin sample | 88 | 82.9% | 74 min | 1.14% | B |
| ONT to IAH · Houstonthin sample | 62 | 88.5% | 48 min | 1.61% | A |
| ONT to HNL · Honoluluthin sample | 62 | 79.0% | 39 min | 0.00% | B+ |
| ONT to PDX · Portlandthin sample | 41 | 97.5% | 19 min | 2.44% | A |
| ONT to STS · Santa Rosathin sample | 31 | 93.5% | 43 min | 0.00% | A+ |
| ONT to BNA · Nashvillethin sample | 31 | 48.4% | 40 min | 0.00% | F+ |
| ONT to BWI · Baltimorethin sample | 31 | 77.4% | 20 min | 0.00% | B+ |
| ONT to HOU · Houstonthin sample | 31 | 71.0% | 23 min | 0.00% | C+ |
| ONT to MDW · Chicagothin sample | 31 | 87.1% | 30 min | 0.00% | A+ |
| ONT to CLT · Charlottethin sample | 31 | 86.7% | 163 min | 3.23% | A− |
| ONT to AUS · Austinthin sample | 31 | 48.4% | 37 min | 0.00% | F+ |
| ONT to DAL · Dallasthin sample | 31 | 80.6% | 45 min | 0.00% | B+ |
| ONT to ORD · Chicagothin sample | 31 | 89.3% | 45 min | 6.45% | A− |
| ONT to JFK · New Yorkthin sample | 31 | 37.9% | 231 min | 6.45% | F− |
Delay causes
What held ONT up in July
Carrier accounts for 42% of the 39,000 delay minutes carriers reported here, and the remaining four split what is left.
- 42%Carrier
- 38%Late-arriving aircraft
- 18%National Airspace System
- 1%Extreme weather
- 0%Security
38% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 39,000 reported delay minutes here, that single category outweighs weather by 30 to one. The split is drawn from 38,607 reported delay minutes.
Cancellations are rare at 0.88%, below the national 2.62% 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.
6.6% of arrivals land an hour or more late, close to the national 11.3%, so a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last a little over an hour, which a normal layover absorbs.
What to do with this
Flying from ONT in July
For a July trip through ONT: plan on this being one of the airport's harder months. The 5am–8am departures held up best at 93.1% on time, and with 6.6% of arrivals an hour or more late, a connection here deserves more slack than the same trip in February would.
Related
Where to go next
- Ontario International (ONT), the whole year
- ONT in September84.8%
- ONT in October81.6%
- 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 August80.9%
Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.