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Route on-time record

ONT to OAK: most on-time flights and the best time to fly

Ontario (Ontario International Airport) to Oakland (Oakland San Francisco Bay Airport). 1,514 nonstop flights in Jun 2025 to May 2026, 87% arrived within 15 minutes and 0.4% were cancelled. The most reliable flight number was Southwest 3659 at 6:00 AM.

Flying on a specific date? We’ll adjust for the month, the weekday and the forecast.

ONT → OAK

Ontario to Oakland: 1,514 nonstop flights a year

On time (12 months)

87%

Cancelled

0.4%

avg delay 9 min

Best time to leave

Before 9 AM

96% on time vs 72% after 9 PM

Most reliable airline

Southwest

86% chance on time

Check ONT to OAK fares

Fares open on our travel partner (Aviasales). Pick the flight number you chose here.

Most reliable nonstop flights

Ranked by the chance the flight operates and arrives within 15 minutes of schedule, from Jun 2025 to May 2026 records.

  1. #1 · Southwest 3659

    6:00 AM → 7:20 AM1h 20m nonstop

    Local times, typical schedule. Last flown 2026-05-31. Same departure also flew as Southwest 4135; its record covers all of them.

    92%

    chance on time

    On time (history)
    93%
    Cancelled
    0.0%
    Avg arrival delay
    10 min
    • Arrived on time 93% of the time (87 flights, Jun 2025 to May 2026).
    • Never cancelled in 87 scheduled flights.
    • Leaves in this route's most on-time window (Before 9 AM: 96% on time; After 9 PM: 72%).

    Moderate track record · 87 flights

    Find Southwest 3659 fares Opens this date on Aviasales

  2. #2 · Southwest 4136

    11:10 AM → 12:35 PM1h 25m nonstop

    Local times, typical schedule. Last flown 2026-04-06.

    92%

    chance on time

    On time (history)
    97%
    Cancelled
    0.0%
    Avg arrival delay
    4 min
    • Arrived on time 97% of the time (33 flights, Jun 2025 to May 2026).
    • Never cancelled in 33 scheduled flights.
    • Short track record (33 flights), so its score leans on the airline's record at this hour.

    Limited track record · 33 flights

    Find Southwest 4136 fares Opens this date on Aviasales

  3. #3 · Southwest 2424

    11:00 AM → 12:20 PM1h 20m nonstop

    Local times, typical schedule. Last flown 2026-05-31.

    90%

    chance on time

    On time (history)
    89%
    Cancelled
    0.0%
    Avg arrival delay
    6 min
    • Arrived on time 89% of the time (55 flights, Jun 2025 to May 2026).
    • Never cancelled in 55 scheduled flights.
    • Short track record (55 flights), so its score leans on the airline's record at this hour.

    Limited track record · 55 flights

    Find Southwest 2424 fares Opens this date on Aviasales

  4. #4 · Southwest 2261

    7:55 PM → 9:20 PM1h 25m nonstop

    Local times, typical schedule. Last flown 2026-04-06.

    89%

    chance on time

    On time (history)
    96%
    Cancelled
    0.0%
    Avg arrival delay
    2 min
    • Arrived on time 96% of the time (28 flights, Jun 2025 to May 2026).
    • Short track record (28 flights), so its score leans on the airline's record at this hour.

    Limited track record · 28 flights

    Find Southwest 2261 fares Opens this date on Aviasales

  5. #5 · Southwest 2168

    4:00 PM → 5:40 PM1h 40m nonstop

    Local times, typical schedule. Last flown 2026-04-06.

    88%

    chance on time

    On time (history)
    93%
    Cancelled
    0.0%
    Avg arrival delay
    2 min
    • Arrived on time 93% of the time (15 flights, Jun 2025 to May 2026).
    • Short track record (15 flights), so its score leans on the airline's record at this hour.

    Limited track record · 15 flights

    Find Southwest 2168 fares Opens this date on Aviasales

  6. #6 · Southwest 2045

    5:05 PM → 6:30 PM1h 25m nonstop

    Local times, typical schedule. Last flown 2026-04-01.

    86%

    chance on time

    On time (history)
    100%
    Cancelled
    0.0%
    Avg arrival delay
    2 min
    • Arrived on time 100% of the time (8 flights, Jun 2025 to May 2026).
    • Short track record (8 flights), so its score leans on the airline's record at this hour.

    Limited track record · 8 flights

    Find Southwest 2045 fares Opens this date on Aviasales

  7. #7 · Southwest 3662

    8:25 PM → 9:45 PM1h 20m nonstop

    Local times, typical schedule. Last flown 2026-05-31.

    81%

    chance on time

    On time (history)
    76%
    Cancelled
    0.0%
    Avg arrival delay
    12 min
    • Arrived on time 76% of the time (55 flights, Jun 2025 to May 2026).
    • Never cancelled in 55 scheduled flights.
    • 82% of its delay minutes came from the plane arriving late from an earlier flight.
    • Short track record (55 flights), so its score leans on the airline's record at this hour.

    Limited track record · 55 flights

    Find Southwest 3662 fares Opens this date on Aviasales

  8. #8 · Southwest 3143

    9:15 PM → 10:35 PM1h 20m nonstop

    Local times, typical schedule. Last flown 2026-05-31.

    79%

    chance on time

    On time (history)
    63%
    Cancelled
    0.0%
    Avg arrival delay
    21 min
    • Arrived on time 63% of the time (8 flights, Jun 2025 to May 2026).
    • Leaves in this route's least on-time window (After 9 PM: 72% on time; Before 9 AM: 96%).
    • 86% of its delay minutes came from the plane arriving late from an earlier flight.
    • Short track record (8 flights), so its score leans on the airline's record at this hour.

    Limited track record · 8 flights

    Find Southwest 3143 fares Opens this date on Aviasales

  9. #9 · Southwest 3661

    3:35 PM → 4:55 PM1h 20m nonstop

    Local times, typical schedule. Last flown 2026-05-29.

    79%

    chance on time

    On time (history)
    72%
    Cancelled
    0.0%
    Avg arrival delay
    14 min
    • Arrived on time 72% of the time (39 flights, Jun 2025 to May 2026).
    • Never cancelled in 39 scheduled flights.
    • 80% of its delay minutes came from the plane arriving late from an earlier flight.
    • Short track record (39 flights), so its score leans on the airline's record at this hour.

    Limited track record · 39 flights

    Find Southwest 3661 fares Opens this date on Aviasales

Airlines on this route

Season-adjusted chance of operating and arriving on time.

  • Southwest Airlines86%

    1,514 flights · 87% on time as flown · 0.4% cancel

On time by departure time

All airlines, scheduled local departure, Jun 2025 to May 2026.

  • Before 9 AM96%

    333 flights · avg delay 4 min

  • 9 AM to noon94%

    322 flights · avg delay 3 min

  • Noon to 3 PM87%

    155 flights · avg delay 13 min

  • 3 to 6 PM82%

    340 flights · avg delay 10 min

  • 6 to 9 PM77%

    310 flights · avg delay 14 min

  • After 9 PM72%

    54 flights · avg delay 16 min

Best day: Saturday (91%). Worst: Sunday (81%).

Smarter routing

Nearby airports that run more on time

  • LGB → OAK 89% chance on time

    Long Beach International Airport to Oakland San Francisco Bay Airport · 1,649 flights a year · 36 mi from your airports · yours: 86%

    Rank flightsFares

On time by month

All airlines, Jun 2023 to May 2026. Several years per month, so one stormy season doesn't define a month. Travel-month estimates use this seasonal pattern.

J
90
F
91
M
92
A
85
M
83
J
82
J
86
A
88
S
89
O
86
N
88
D
85

What delays this route

  • Late-arriving aircraft65%
  • Airline (crew, maintenance, boarding)31%
  • Air traffic control and airport volume4%

Share of delay minutes by the cause airlines report to the US DOT.

Historical odds, not a guarantee. Built from the US DOT Bureau of Transportation Statistics on-time reports (Jun 2025 to May 2026), FAA ground stop and delay program advisories, and 20 years of airport weather observations. Covers US airlines that report to the DOT; schedules are flights operated recently, so confirm times when you book. ATIS Alerts is not affiliated with any airline. Fares are what Aviasales travelers saw in recent searches (USD, one way, 1 adult), not live quotes; the partner site shows the current price. Fare links go to our travel partner and may earn us a commission at no cost to you. Affiliate disclosure

ONT to OAK questions

What time of day is best to fly ONT to OAK?
Before 9 AM: 96% of flights arrived on time, against 72% for departures after 9 PM. Later flights inherit delays from earlier ones, so the first departures of the day usually run best.
Which airline is most on time from ONT to OAK?
Southwest, with a season-adjusted 86% chance of operating and arriving on time over 1,514 flights. The adjustment compares each airline with what the route did in the months it flew, so a carrier that skipped a stormy month gets no free credit.
What is the worst month for delays on ONT to OAK?
June (82% on time); the best was March (92%), averaged over Jun 2023 to May 2026.
Is this a prediction for my flight?
No. These are historical odds from the US DOT on-time reports, FAA advisories and airport weather records. Check your flight status and the FAA delay board on the day you fly.

More routes from ONT

Live status: FAA delays and ground stops