86% of flights from Ontario to Atlanta arrived on time over the past 12 months. That is better than the typical U.S. route. The 10 p.m. departures ran on time 90% of the time; the noon ones 80%. 8% of flights arrived more than an hour late or not at all.
How late?
The on-time rate treats a flight 20 minutes late the same as one 5 hours late. Here's the split for ONT → ATL: when a flight was late, it was under 45 minutes late 45% of the time. About 1 in 20 flights landed an hour or more late, and 1 in 72 three hours or more; 1.8% were cancelled outright.
- On time or early86%
- 15–30 min late3.4%
- 30–60 min late2.4%
- 1–2 hours late2.6%
- 2–3 hours late1.0%
- 3+ hours late1.4%
- Diverted1.1%
- Cancelled1.8%
Share of all 934 scheduled flights, past 12 months, by arrival time against schedule.
By airline
| Airline | Flights | On time | Cancelled | Typical arrival | 1h+ late | Avg when late | Operated by |
|---|---|---|---|---|---|---|---|
| Delta Air Lines | 934 | 86% | 1.8% | −10 min | 4.9% | +100 min | Delta Air Lines |
Airline = the name on the ticket. Regional flights (e.g. "Delta Connection") count under the ticketing airline, and the operator is listed.
Best time of day to fly
On-time rate by scheduled departure hour (local time at ONT). Delays build through the day as late planes knock on, so early flights usually do best.
Last flight of the day
On ONT → ATL, each airline's last flight of the day was cancelled 1.9% of the time, against 1.8% for its earlier flights, about the same. It arrived 3+ hours late 1.4% of the time (earlier flights: 1.4%). It matters more than the numbers suggest. Miss an earlier flight and there's another one that evening; miss the last one and you're usually waiting until morning.
| Airline | Last departure | Last: cancelled | Last: 3h+ late | Earlier: cancelled | Next morning |
|---|---|---|---|---|---|
| Delta Air Lines | 10:00 p.m. | 1.9% | 1.4% | 1.8% | first flight 7:05 a.m. |
Last flight = the airline's last scheduled departure on this route that day, on days it flies the route at least twice; past 12 months. Times are typical scheduled times over the latest three months.
By month
Each calendar month pooled over 2023–2026. Best: September (96%). Worst: July (81%).
By day of week
| Day | Flights | On time | Cancelled |
|---|---|---|---|
| Monday | 141 | 84% | 1.4% |
| Tuesday | 131 | 92% | 1.5% |
| Wednesday | 129 | 93% | 0.0% |
| Thursday | 137 | 91% | 0.7% |
| Friday | 139 | 82% | 2.9% |
| Saturday | 116 | 81% | 3.5% |
| Sunday | 141 | 82% | 2.8% |
Why flights were late
Share of delay minutes on flights 15+ minutes late, as reported to BTS by the airlines.
Cancellations: airline 14 · weather 3
Month by month
Not enough months with data to draw a trend.
Flight numbers on this route
Regular flights with at least 120 scheduled trips in the past year. Sorted by departure time.
| Flight | Departs | Flights | On time | Cancelled | Typical arrival | Operated by |
|---|---|---|---|---|---|---|
| DL 761 | 7:05 a.m. | 364 | 88% | 1.9% | −8 min | Delta Air Lines |
| DL 665 | 12:41 p.m. | 365 | 81% | 1.6% | −10 min | Delta Air Lines |
Worst days in the past year
| Date | Flights | On time | Cancelled |
|---|---|---|---|
| Dec 14, 2025 | 3 | 0% | 1 |
| Nov 10, 2025 | 3 | 33% | 1 |
| Dec 29, 2025 | 3 | 33% | 1 |
| May 8, 2026 | 3 | 33% | 1 |
| Oct 26, 2025 | 3 | 33% | 0 |
Nearby airport alternatives
Other ways to make the same trip, using airports within 60 miles of Ontario or Atlanta. None has been clearly more reliable than ONT → ATL.
| Route | Flights | On time | Cancelled |
|---|---|---|---|
| ONT → ATL (this route) | 934 | 86% | 1.8% |
| SNA → ATL Orange County John Wayne to Atlanta Hartsfield-Jackson | 1,020 | 79% | 1.0% |
| LAX → ATL Los Angeles LAX to Atlanta Hartsfield-Jackson | 4,843 | 78% | 0.9% |
Questions
How often are flights from ONT to ATL on time?
86% of 934 scheduled flights from Ontario, CA to Atlanta, GA arrived within 15 minutes of schedule between September 2025 and August 2026. 1.8% were cancelled.
What is the best time of day to fly ONT to ATL?
Flights scheduled to leave at 10 p.m. were the most reliable (90% on time). The noon departures were the least (80%).
What month has the most delays from ONT to ATL?
July (81% on time). The best month is September (96%), over 2023–2026.
Is the last flight of the day from ONT to ATL more likely to be cancelled?
Not much. Each airline's last ONT–ATL flight of the day was cancelled 1.9% of the time over the past year, against 1.8% for its earlier flights. If the last flight is cancelled, the next one is usually the following morning.
Related
- ATL → ONT (return)
- Ontario (ONT) delays by hour
- Flights into Atlanta Hartsfield-Jackson (ATL)
- Delta Air Lines on-time record
- Connecting off this flight? Check the risk
Domestic flights by the airlines that report to the U.S. DOT, plus their regional partners. "On time" means arriving less than 15 minutes after schedule; cancelled and diverted flights count as not on time. Past performance is a guide, not a forecast. Method.