Route profile
ONT→OAK
Flight reliability, delays and best times to fly from Ontario to Oakland, 362 miles.
Right now
Aviation weather is not currently a factor.
Aviation weather is not currently a factor.
Route reliability
July 2023 – July 2026
Better than 96% of comparable major US routes (4,598 compared)
Calculated from 4,811 flights. How this is calculated · What counts as on time
ONT → OAK arrives on time 87.1% of the time; the return trip, OAK → ONT, arrives on time 84.5% of the time, a 2.6-point gap between the two directions of the same city pair.
ONT → OAK spends 15.6 minutes on the ground on a 362-mile trip: 9.9 minutes from pushback to wheels-up at ONT and 5.8 minutes from touchdown to gate at OAK.
Source: US DOT Bureau of Transportation Statistics · Data covering July 2023 – July 2026
What sets this route apart
Where ONT to OAK differs most from similar routes by hour, weekday, month and airline, July 2023 – July 2026.
ONT to OAK is at its best against routes of similar length for flights scheduled at 7 PM: 81.4% arrive on time, 11.5 points ahead of the 69.9% those routes manage at that hour. Against all other routes the gap is 13.6 points.
ONT to OAK holds up on Mondays better than routes of similar length do: 88.7% on time to their 78.2%, a 10.5 points lead. Against all other routes the gap is 11.5 points.
July is kinder to ONT to OAK than to routes of similar length: 87.0% on time against 71.6%, 15.4 points better. Against all other routes the gap is 17.3 points.
Southwest Airlines does better on ONT to OAK than on its routes of similar length: 87.1% on time here, 80.1% there, 7 points apart. Against all other routes the gap is 9.7 points.
ONT to OAK against comparable routes
July 2023 – July 2026| Measure | This route | Compared with | Them | Gap | Flights behind it |
|---|---|---|---|---|---|
| Hour: 7 PM departures | 81.4% | routes of similar length | 69.9% | +11.5 pts | 242 here, 89,911 there |
| Weekday: Monday | 88.7% | routes of similar length | 78.2% | +10.5 pts | 741 here, 227,139 there |
| Month: July | 87.0% | routes of similar length | 71.6% | +15.4 pts | 515 here, 164,792 there |
| Airline: Southwest Airlines | 87.1% | routes of similar length | 80.1% | +7.0 pts | 4,783 here, 503,287 there |
Each comparison pools the flights of other routes, with this route’s own left out. Similar length means within 15% of this route’s 362 miles, with at least 5 such routes. A bucket is set against the most comparable group that has enough flights: similar length, then the same origin (at least 3 routes), then all other routes. Hours, weekdays and months appear only where both sides have 120 completed flights, and airlines where both have 600. The gap must be at least 2 points and 2 standard errors, and only the largest gap each way is kept per measure. These are differences in the flights counted, not causes.
When it goes wrong
July 2023 – July 2026
22 min late
against a median of 10 min early
Percentiles over 4,811 operations; cancelled and diverted flights are counted separately.
Will your connection be tight enough?
Layovers at OAK after arriving from ONT.
| Connection time | Chance of missing | Reads as |
|---|---|---|
| 30 min | 25% | High risk |
| 45 min | 12% | Some risk |
| 60 min | 7.5% | Some risk |
| 90 min | 3.7% | Low risk |
| 120 min | 2.2% | Low risk |
This is one leg of a connection. Gate changes and the next flight's own schedule matter too. And a connection can fail before delay is even the question — this route cancels 0.54% of the time and diverts 0.04% of the time, which a late arrival never shows up in.
Chance of missing is the share of 4,783 arrivals on this route that landed later than the connection time less 30 minutes to reach the next gate.
The worst tenth of arrivals on this route land at least 22 minutes late (90th-percentile gate arrival delay), over 4,811 operations.
Any other layover length: connection checker.
Best time to fly
ONT → OAK flights departing 5–9 AM arrived on time 96.6% of the time, against 69.5% for 9 PM–5 AM departures, a gap of 27.1 percentage points.
By departure window
By departure hour
- 12 AM to 4 AM: too few flights to score
- 5 AM: 97.1% on time from 140 flights
- 6 AM: 96.6% on time from 673 flights
- 7 AM: 97.0% on time from 166 flights
- 8 AM: 96.1% on time from 205 flights
- 9 AM: 94.8% on time from 233 flights
- 10 AM: 91.3% on time from 394 flights
- 11 AM: 92.8% on time from 322 flights
- 12 PM: 91.7% on time from 169 flights
- 1 PM: 84.1% on time from 168 flights
- 2 PM: 84.6% on time from 210 flights
- 3 PM: 81.1% on time from 334 flights
- 4 PM: 81.0% on time from 335 flights
- 5 PM: 79.1% on time from 270 flights
- 6 PM: 79.3% on time from 382 flights
- 7 PM: 81.4% on time from 244 flights
- 8 PM: 79.8% on time from 423 flights
- 9 PM: 70.1% on time from 139 flights
- 10 PM to 11 PM: too few flights to score
Why ONT → OAK runs late
July 2023 – July 2026
the inbound aircraft was late, so this flight started late
crew, maintenance, boarding and fueling, all within the carrier’s control
airspace and airport capacity, including weather-driven flow control
weather severe enough to stop this flight specifically
screening or terminal security incidents
Share of the delay minutes US DOT attributed to each cause for ONT → OAK. Only delays of 15 minutes or more are attributed. What the five causes mean
Late-arriving aircraft is the largest cause on ONT → OAK, at 72.2%: flights here mostly leave late because the plane came in late, and the day shows it: 5–9 AM departures arrived on time 96.6% of the time and 9 PM–5 AM departures 69.5%.
Airlines on this route
Carriers with at least 200 flights, by the airline that operated each one.
| Carrier | Flights | On time | Cancelled | Median delay | Severe |
|---|---|---|---|---|---|
| Southwest Airlines | 4,811 | 87.1% | 0.54% | -10 min | 3.8% |
Other ways to fly Los Angeles to San Francisco
Airport pairs in the same two city markets, as the DOT defines them.
| Route | Flights | On time | Cancelled | Median delay | Score |
|---|---|---|---|---|---|
| LAX→SFO Los Angeles to San Francisco | 34,819 | 69.3% | 0.67% | -1 min | 55 |
| LAX→SJC Los Angeles to San Jose | 15,597 | 86.5% | 0.35% | -9 min | 87 |
| SNA→SFO Santa Ana to San Francisco | 13,797 | 71.6% | 1.26% | -3 min | 54 |
| ONT→OAK this route Ontario to Oakland | 4,811 | 87.1% | 0.54% | -10 min | 87 |
LAX → SJC is the most reliable pairing for this journey at 86.5% on time, against 71.6% for SNA → SFO.
Flying to OAK from the Los Angeles area? Compare ONT, LAX, SNA, BUR for OAK, with the same test for what counts as a real difference.
Weekly and seasonal patterns
By day of week
Tuesday is historically the most reliable day and Sunday the least, a gap of 10.7 percentage points.
By month
- Jan: 90.3%
- Feb: 90.7%
- Mar: 92.5%
- Apr: 85.3%
- May: 82.7%
- Jun: 80.9%
- Jul: 87.0%
- Aug: 87.8%
- Sep: 89.2%
- Oct: 86.4%
- Nov: 88.4%
- Dec: 84.9%
June is historically the weakest month and March the strongest, a spread of 11.6 percentage points.
Reliability over time
July 2023 – July 2026
- July 2023: 83.3% from 134 flights
- August 2023: 80.4% from 143 flights
- September 2023: 83.1% from 142 flights
- October 2023: 85.3% from 144 flights
- November 2023: 91.7% from 144 flights
- December 2023: 91.4% from 152 flights
- January 2024: 91.1% from 135 flights
- February 2024: too few flights to score (116)
- March 2024: 87.6% from 130 flights
- April 2024: 79.8% from 129 flights
- May 2024: 76.0% from 131 flights
- June 2024: 83.2% from 131 flights
- July 2024: 85.6% from 133 flights
- August 2024: 92.7% from 137 flights
- September 2024: 93.9% from 132 flights
- October 2024: 92.4% from 134 flights
- November 2024: 89.1% from 129 flights
- December 2024: 82.3% from 125 flights
- January 2025: 89.1% from 120 flights
- February 2025: too few flights to score (116)
- March 2025: 93.4% from 136 flights
- April 2025: 90.8% from 130 flights
- May 2025: 90.3% from 147 flights
- June 2025: 83.0% from 135 flights
- July 2025: 88.1% from 135 flights
- August 2025: 90.4% from 135 flights
- September 2025: 91.0% from 133 flights
- October 2025: 81.6% from 136 flights
- November 2025: 84.1% from 129 flights
- December 2025: 79.3% from 121 flights
- January 2026: 90.7% from 120 flights
- February 2026: too few flights to score (115)
- March 2026: 96.7% from 121 flights
- April 2026: too few flights to score (116)
- May 2026: too few flights to score (118)
- June 2026: too few flights to score (111)
- July 2026: too few flights to score (116)
Over the most recent 12 months (2025-08 to 2026-07), on-time arrivals averaged 86.5% against 89.8% in the 12 months before — declining by 3.3 percentage points.
Data and methodology
Calculated by FlyerIntel from 4,811 ONT → OAK flight records from the US DOT Bureau of Transportation Statistics, covering July 2023 – July 2026. Late means 15 or more minutes past scheduled arrival; cancelled and diverted flights are left out of on-time rates.
Full methodology · Data sources · Report a problem
Related research: How Long a Layover Needs to Be · Two Airlines on One Route · Best Time of Day to Fly From Major US Airports
Analysis last recomputed