Route profile
SFO→ONT
Flight reliability, delays and best times to fly from San Francisco to Ontario, 363 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 62% of comparable major US routes (4,598 compared)
Calculated from 4,430 flights. How this is calculated
SFO → ONT arrives on time 80.5% of the time; the return trip, ONT → SFO, arrives on time 71.4% of the time, a 9.1-point gap between the two directions of the same city pair.
SFO → ONT spends 25.6 minutes on the ground on a 363-mile trip: 20.3 minutes from pushback to wheels-up at SFO and 5.4 minutes from touchdown to gate at ONT.
Source: US DOT Bureau of Transportation Statistics · Data covering July 2023 – July 2026
What sets this route apart
Where SFO to ONT differs most from similar routes by hour, weekday, month and airline, July 2023 – July 2026.
SFO to ONT struggles most at 11 AM: 69.1% of its flights scheduled then arrive on time, 14.3 points behind the 83.4% on routes of similar length at the same hour. Against all other routes the gap is 11.9 points.
SFO to ONT is at its best against routes of similar length for flights scheduled at 6 PM: 83.1% arrive on time, 13.4 points ahead of the 69.7% those routes manage at that hour. Against all other routes the gap is 14.5 points.
In November, SFO to ONT runs 7.9 points below routes of similar length, 75.9% on time to 83.8%. Against all other routes the gap is 7.5 points.
July is kinder to SFO to ONT than to routes of similar length: 76.6% on time against 71.6%, 5 points better. Against all other routes the gap is 6.9 points.
United Airlines does better on SFO to ONT than on its routes of similar length: 82.9% on time here, 77.9% there, 5 points apart. Against all other routes the gap is 3 points.
SFO to ONT against comparable routes
July 2023 – July 2026| Measure | This route | Compared with | Them | Gap | Flights behind it |
|---|---|---|---|---|---|
| Hour: 11 AM departures | 69.1% | routes of similar length | 83.4% | −14.3 pts | 223 here, 85,749 there |
| Hour: 6 PM departures | 83.1% | routes of similar length | 69.7% | +13.4 pts | 142 here, 94,408 there |
| Month: November | 75.9% | routes of similar length | 83.8% | −7.9 pts | 424 here, 120,191 there |
| Month: July | 76.6% | routes of similar length | 71.6% | +5.0 pts | 488 here, 163,915 there |
| Airline: United Airlines | 82.9% | routes of similar length | 77.9% | +5.0 pts | 1,909 here, 149,124 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 363 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
39 min late
against a median of 6 min early
Percentiles over 4,430 operations; cancelled and diverted flights are counted separately.
Will your connection be tight enough?
Layovers at ONT after arriving from SFO.
| Connection time | Chance of missing | Reads as |
|---|---|---|
| 30 min | 36% | Likely to miss |
| 45 min | 19% | High risk |
| 60 min | 12% | Some risk |
| 90 min | 6.3% | Some risk |
| 120 min | 3.8% | 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 1.02% of the time and diverts 0.09% of the time, which a late arrival never shows up in.
Chance of missing is the share of 4,381 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 39 minutes late (90th-percentile gate arrival delay), over 4,430 operations.
Any other layover length: connection checker.
Best time to fly
SFO → ONT flights departing 5–9 AM arrived on time 89.5% of the time, against 76.3% for 9 PM–5 AM departures, a gap of 13.2 percentage points.
By departure window
By departure hour
- 12 AM to 7 AM: too few flights to score
- 8 AM: 89.7% on time from 686 flights
- 9 AM: 81.0% on time from 178 flights
- 10 AM: 80.7% on time from 461 flights
- 11 AM: 69.1% on time from 224 flights
- 12 PM: too few flights to score
- 1 PM: 78.1% on time from 220 flights
- 2 PM: 81.2% on time from 134 flights
- 3 PM: too few flights to score
- 4 PM: 80.3% on time from 937 flights
- 5 PM: too few flights to score
- 6 PM: 83.1% on time from 143 flights
- 7 PM to 8 PM: too few flights to score
- 9 PM: 78.1% on time from 691 flights
- 10 PM: 69.4% on time from 269 flights
- 11 PM: too few flights to score
Why SFO → ONT 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
Share of the delay minutes US DOT attributed to each cause for SFO → ONT. Only delays of 15 minutes or more are attributed.
Late-arriving aircraft is the largest cause on SFO → ONT, at 53.4%: flights here mostly leave late because the plane came in late, and the day shows it: 5–9 AM departures arrived on time 89.5% of the time and 9 PM–5 AM departures 76.3%.
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 |
|---|---|---|---|---|---|
| United Airlines | 1,919 | 82.9% | 0.42% | -7 min | 5.0% |
| SkyWest Airlines | 1,677 | 82.5% | 1.25% | -6 min | 5.7% |
| Frontier Airlines | 834 | 70.7% | 1.92% | -2 min | 11.0% |
United Airlines flew 43.3% of the 4,430 flights listed. Frontier Airlines cancelled 1.92% of its flights here against 0.42% for United Airlines.
United Airlines arrived on time 12.2 percentage points more often than Frontier Airlines on this route.
Other ways to fly San Francisco to Los Angeles
Airport pairs in the same two city markets, as the DOT defines them.
| Route | Flights | On time | Cancelled | Median delay | Score |
|---|---|---|---|---|---|
| SFO→LAX San Francisco to Los Angeles | 34,804 | 77.1% | 0.70% | -5 min | 67 |
| SJC→LAX San Jose to Los Angeles | 15,614 | 86.7% | 0.37% | -10 min | 88 |
| SFO→SNA San Francisco to Santa Ana | 13,715 | 80.2% | 1.13% | -6 min | 72 |
| SFO→ONT this route San Francisco to Ontario | 4,430 | 80.5% | 1.02% | -6 min | 70 |
SJC → LAX is the most reliable pairing for this journey at 86.7% on time, against 77.1% for SFO → LAX.
Flying to ONT from the San Francisco area? Compare SFO, SJC, OAK for ONT, with the same test for what counts as a real difference.
Flights on this route
Flight numbers with at least 600 operations here and still on the schedule.
| Flight | Scheduled | Operations | On time |
|---|---|---|---|
| F92678 Frontier Airlines | 10:11 PM | 604 | 67.3% |
Weekly and seasonal patterns
By day of week
Wednesday is historically the most reliable day and Monday the least, a gap of 7.3 percentage points.
By month
- Jan: 84.7%
- Feb: 81.3%
- Mar: 81.6%
- Apr: 84.5%
- May: 80.7%
- Jun: 73.9%
- Jul: 76.6%
- Aug: 81.8%
- Sep: 82.6%
- Oct: 86.2%
- Nov: 75.9%
- Dec: 76.4%
June is historically the weakest month and October the strongest, a spread of 12.3 percentage points.
Reliability over time
July 2023 – July 2026
- July 2023: 87.0% from 138 flights
- August 2023: 87.9% from 120 flights
- September 2023: 88.8% from 134 flights
- October 2023: 89.6% from 163 flights
- November 2023: 82.9% from 147 flights
- December 2023: too few flights to score (117)
- January 2024: too few flights to score (99)
- February 2024: too few flights to score (98)
- March 2024: 73.9% from 120 flights
- April 2024: too few flights to score (90)
- May 2024: too few flights to score (92)
- June 2024: too few flights to score (86)
- July 2024: 78.0% from 127 flights
- August 2024: 81.3% from 140 flights
- September 2024: 81.1% from 148 flights
- October 2024: 91.5% from 165 flights
- November 2024: 74.9% from 180 flights
- December 2024: 78.3% from 140 flights
- January 2025: too few flights to score (101)
- February 2025: too few flights to score (105)
- March 2025: too few flights to score (118)
- April 2025: 92.2% from 153 flights
- May 2025: 80.2% from 131 flights
- June 2025: too few flights to score (104)
- July 2025: too few flights to score (104)
- August 2025: too few flights to score (109)
- September 2025: too few flights to score (108)
- October 2025: too few flights to score (114)
- November 2025: too few flights to score (105)
- December 2025: too few flights to score (104)
- January 2026: too few flights to score (93)
- February 2026: too few flights to score (79)
- March 2026: too few flights to score (104)
- April 2026: 83.1% from 124 flights
- May 2026: 78.4% from 127 flights
- June 2026: 71.4% from 120 flights
- July 2026: 68.3% from 123 flights
Over the most recent 12 months (2025-08 to 2026-07), on-time arrivals averaged 76.4% against 82.0% in the 12 months before — declining by 5.6 percentage points.
Data and methodology
Calculated by FlyerIntel from 4,430 SFO → ONT 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