Historical on-time performance
Atlanta to Ontario
1,900 miData through Dec 2025Source: US DOT · BTS
Flights on ATL–ONT arrive on time 74% of the time over the last 12 months.
On-time rate74%arrived within 15 min
p90 delay40 min1 in 10 flights is worse (tail risk)
Cancelled1.5%of scheduled flights
based on 930 flights over the last 12 months. On-time means arriving within 15 minutes (BTS standard).
By airline
How each carrier compares
- Delta Air LinesOn-time74%Medianon timep9040 minCancel1.5%Flights930
Why flights run late
Delay causes
- Airline47%
- Weather7%
- Air traffic (NAS)22%
- Late aircraft24%
- Security0%
Most delay minutes here are attributed to Airline.
Over time
On-time trend
By season
On-time rate by month
When to fly
Best time to fly ATL → ONT
All airlines · rolling 36 months (2023-01 .. 2025-12).
Best time of day
Mornings are the most reliable time of day to fly this route — 83% on time.
- Mornings83% on time · p90 25 min · 1,028 flights
- Middays75% on time · p90 40 min · 152 flights · limited
- Evenings71% on time · p90 50 min · 724 flights
- Overnights67% on time · p90 55 min · 981 flights
Best day of week
On-time rates are fairly even by day on this route — ranging from 70% to 78% on time.
- Wednesdays78% on time · p90 35 min · 407 flights
- Tuesdays78% on time · p90 30 min · 398 flights
- Thursdays75% on time · p90 35 min · 436 flights
- Saturdays75% on time · p90 45 min · 368 flights
- Fridays72% on time · p90 50 min · 435 flights
- Mondays72% on time · p90 45 min · 436 flights
- Sundays70% on time · p90 65 min · 437 flights
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