Route on-time record
OAK to ONT: most on-time flights and the best time to fly
Oakland (Oakland San Francisco Bay Airport) to Ontario (Ontario International Airport). 1,512 nonstop flights in Jun 2025 to May 2026, 83% arrived within 15 minutes and 0.4% were cancelled. The most reliable flight number was Southwest 516 at 6:05 AM.
Flying on a specific date? We’ll adjust for the month, the weekday and the forecast.
OAK → ONT
Oakland to Ontario: 1,512 nonstop flights a year
On time (12 months)
83%
Cancelled
0.4%
avg delay 10 min
Best time to leave
Before 9 AM
98% on time vs 71% 6 to 9 PM
Most reliable airline
Southwest
83% chance on time
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 · Southwest 516
6:05 AM → 7:25 AM1h 20m nonstop
Local times, typical schedule. Last flown 2026-05-31. Same departure also flew as Southwest 2084; its record covers all of them.
95%
chance on time
- On time (history)
- 95%
- Cancelled
- 0.0%
- Avg arrival delay
- 2 min
- Arrived on time 95% of the time (79 flights, Jun 2025 to May 2026).
- Never cancelled in 79 scheduled flights.
- Leaves in this route's most on-time window (Before 9 AM: 98% on time; 6 to 9 PM: 71%).
Moderate track record · 79 flights
Find Southwest 516 fares Opens this date on Aviasales#2 · Southwest 556
10:45 AM → 12:05 PM1h 20m nonstop
Local times, typical schedule. Last flown 2026-05-27.
87%
chance on time
- On time (history)
- 88%
- Cancelled
- 0.0%
- Avg arrival delay
- 6 min
- Arrived on time 88% of the time (24 flights, Jun 2025 to May 2026).
- Short track record (24 flights), so its score leans on the airline's record at this hour.
Limited track record · 24 flights
Find Southwest 556 fares Opens this date on Aviasales#3 · Southwest 101
10:55 AM → 12:15 PM1h 20m nonstop
Local times, typical schedule. Last flown 2026-05-31. Same departure also flew as Southwest 1966; its record covers all of them.
85%
chance on time
- On time (history)
- 83%
- Cancelled
- 0.0%
- Avg arrival delay
- 7 min
- Arrived on time 83% of the time (53 flights, Jun 2025 to May 2026).
- Never cancelled in 53 scheduled flights.
- Short track record (53 flights), so its score leans on the airline's record at this hour.
Limited track record · 53 flights
Find Southwest 101 fares Opens this date on Aviasales#4 · Southwest 4073
3:25 PM → 4:45 PM1h 20m nonstop
Local times, typical schedule. Last flown 2026-04-06.
84%
chance on time
- On time (history)
- 91%
- Cancelled
- 0.0%
- Avg arrival delay
- 4 min
- Arrived on time 91% of the time (23 flights, Jun 2025 to May 2026).
- Short track record (23 flights), so its score leans on the airline's record at this hour.
Limited track record · 23 flights
Find Southwest 4073 fares Opens this date on Aviasales#5 · Southwest 1415
12:05 PM → 1:25 PM1h 20m nonstop
Local times, typical schedule. Last flown 2026-04-01.
82%
chance on time
- On time (history)
- 75%
- Cancelled
- 0.0%
- Avg arrival delay
- 17 min
- Arrived on time 75% 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 1415 fares Opens this date on Aviasales#6 · Southwest 4669
11:05 AM → 12:30 PM1h 25m nonstop
Local times, typical schedule. Last flown 2026-04-06.
81%
chance on time
- On time (history)
- 73%
- Cancelled
- 0.0%
- Avg arrival delay
- 10 min
- Arrived on time 73% of the time (15 flights, Jun 2025 to May 2026).
- 56% of its delay minutes came from the plane arriving late from an earlier flight.
- Short track record (15 flights), so its score leans on the airline's record at this hour.
Limited track record · 15 flights
Find Southwest 4669 fares Opens this date on Aviasales#7 · Southwest 2829
9:55 PM → 11:20 PM1h 25m nonstop
Local times, typical schedule. Last flown 2026-04-05.
77%
chance on time
- On time (history)
- 67%
- Cancelled
- 0.0%
- Avg arrival delay
- 21 min
- Arrived on time 67% of the time (18 flights, Jun 2025 to May 2026).
- 55% of its delay minutes came from the plane arriving late from an earlier flight.
- Short track record (18 flights), so its score leans on the airline's record at this hour.
Limited track record · 18 flights
Find Southwest 2829 fares Opens this date on Aviasales#8 · Southwest 540
4:00 PM → 5:20 PM1h 20m nonstop
Local times, typical schedule. Last flown 2026-05-31.
72%
chance on time
- On time (history)
- 59%
- Cancelled
- 0.0%
- Avg arrival delay
- 20 min
- Arrived on time 59% of the time (54 flights, Jun 2025 to May 2026).
- Never cancelled in 54 scheduled flights.
- 64% of its delay minutes came from the plane arriving late from an earlier flight.
- Short track record (54 flights), so its score leans on the airline's record at this hour.
Limited track record · 54 flights
Find Southwest 540 fares Opens this date on Aviasales#9 · Southwest 1087
8:00 PM → 9:20 PM1h 20m nonstop
Local times, typical schedule. Last flown 2026-05-31. Same departure also flew as Southwest 1142; its record covers all of them.
64%
chance on time
- On time (history)
- 53%
- Cancelled
- 0.0%
- Avg arrival delay
- 28 min
- Arrived on time 53% of the time (66 flights, Jun 2025 to May 2026).
- Never cancelled in 66 scheduled flights.
- Leaves in this route's least on-time window (6 to 9 PM: 71% on time; Before 9 AM: 98%).
- 52% of its delay minutes came from the plane arriving late from an earlier flight.
Moderate track record · 66 flights
Find Southwest 1087 fares Opens this date on Aviasales
Airlines on this route
Season-adjusted chance of operating and arriving on time.
- Southwest Airlines83%
1,512 flights · 83% on time as flown · 0.4% cancel
On time by departure time
All airlines, scheduled local departure, Jun 2025 to May 2026.
- Before 9 AM98%
364 flights · avg delay 1 min
- 9 AM to noon88%
251 flights · avg delay 7 min
- Noon to 3 PM86%
281 flights · avg delay 7 min
- 3 to 6 PM74%
259 flights · avg delay 15 min
- 6 to 9 PM71%
322 flights · avg delay 18 min
Best day: Saturday (90%). Worst: Friday (79%).
Smarter routing
Nearby airports that run more on time
SJC → LAX 87% chance on time
Norman Y. Mineta San Jose International Airport to Los Angeles International Airport · 4,405 flights a year · 76 mi from your airports · yours: 83%
SJC → SNA 87% chance on time
Norman Y. Mineta San Jose International Airport to John Wayne Orange County International Airport · 2,679 flights a year · 59 mi from your airports · yours: 83%
OAK → LGB 86% chance on time
Oakland San Francisco Bay Airport to Long Beach International Airport · 1,649 flights a year · 36 mi from your airports · yours: 83%
OAK → SNA 86% chance on time
Oakland San Francisco Bay Airport to John Wayne Orange County International Airport · 2,387 flights a year · 30 mi from your airports · yours: 83%
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.
What delays this route
- Late-arriving aircraft55%
- Airline (crew, maintenance, boarding)41%
- Air traffic control and airport volume5%
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
OAK to ONT questions
- What time of day is best to fly OAK to ONT?
- Before 9 AM: 98% of flights arrived on time, against 71% for departures 6 to 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 OAK to ONT?
- Southwest, with a season-adjusted 83% chance of operating and arriving on time over 1,512 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 OAK to ONT?
- May (80% on time); the best was January (91%), 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 OAK
- ONT to OAK (return)
- OAK to LAS 80%
- OAK to SAN 69%
- OAK to BUR 82%
- OAK to SNA 86%
- OAK to LAX 81%
- OAK to PHX 78%
- OAK to SEA 77%
- OAK to SLC 89%
- OAK to LGB 87%
- OAK to DEN 73%
- OAK to PDX 81%
- OAK to HNL 80%
Live status: FAA delays and ground stops