Route on-time record
ONT to ATL: most on-time flights and the best time to fly
Ontario (Ontario International Airport) to Atlanta (Hartsfield Jackson Atlanta International Airport). 941 nonstop flights in Jun 2025 to May 2026, 90% arrived within 15 minutes and 1.8% were cancelled. The most reliable flight number was Delta 2891 at 10:00 PM.
Flying on a specific date? We’ll adjust for the month, the weekday and the forecast.
ONT → ATL
Ontario to Atlanta: 941 nonstop flights a year
On time (12 months)
90%
Cancelled
1.8%
avg delay 11 min
Best time to leave
Before 9 AM
93% on time vs 81% noon to 3 PM
Most reliable airline
Delta
88% 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 · Delta 2891
10:00 PM → 5:14 AM4h 14m nonstop
Local times, typical schedule. Last flown 2026-05-31.
94%
chance on time
- On time (history)
- 100%
- Cancelled
- 0.0%
- Avg arrival delay
- 0 min
- Arrived on time 100% of the time (25 flights, Jun 2025 to May 2026).
- Short track record (25 flights), so its score leans on the airline's record at this hour.
Limited track record · 25 flights
Find Delta 2891 fares Opens this date on Aviasales#2 · Delta 761
7:05 AM → 5:28 AM4h 10m nonstop
Local times, typical schedule. Last flown 2026-05-31.
90%
chance on time
- On time (history)
- 91%
- Cancelled
- 1.9%
- Avg arrival delay
- 12 min
- Arrived on time 91% of the time (356 flights, Jun 2025 to May 2026).
- Leaves in this route's most on-time window (Before 9 AM: 93% on time; Noon to 3 PM: 81%).
Strong track record · 356 flights
Find Delta 761 fares Opens this date on Aviasales#3 · Delta 447
10:15 PM → 5:22 AM4h 07m nonstop
Local times, typical schedule. Last flown 2026-05-06.
87%
chance on time
- On time (history)
- 83%
- Cancelled
- 0.0%
- Avg arrival delay
- 36 min
- Arrived on time 83% 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 Delta 447 fares Opens this date on Aviasales#4 · Delta 665
12:57 PM → 8:01 PM4h 10m nonstop
Local times, typical schedule. Last flown 2026-05-31.
84%
chance on time
- On time (history)
- 85%
- Cancelled
- 1.4%
- Avg arrival delay
- 10 min
- Arrived on time 85% of the time (353 flights, Jun 2025 to May 2026).
- Leaves in this route's least on-time window (Noon to 3 PM: 81% on time; Before 9 AM: 93%).
Strong track record · 353 flights
Find Delta 665 fares Opens this date on Aviasales
Airlines on this route
Season-adjusted chance of operating and arriving on time.
- Delta Air Lines88%
941 flights · 90% on time as flown · 1.8% cancel
On time by departure time
All airlines, scheduled local departure, Jun 2025 to May 2026.
- Before 9 AM93%
266 flights · avg delay 10 min
- 9 AM to noon90%
172 flights · avg delay 5 min
- Noon to 3 PM81%
193 flights · avg delay 15 min
- After 9 PM93%
310 flights · avg delay 12 min
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
- Airline (crew, maintenance, boarding)62%
- Late-arriving aircraft27%
- Air traffic control and airport volume9%
- Security2%
- Severe weather1%
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 ATL questions
- What time of day is best to fly ONT to ATL?
- Before 9 AM: 93% of flights arrived on time, against 81% for departures noon to 3 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 ATL?
- Delta, with a season-adjusted 88% chance of operating and arriving on time over 941 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 ATL?
- June (86% on time); the best was September (97%), 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
- ATL to ONT (return)
- ONT to PHX 83%
- ONT to DEN 79%
- ONT to SEA 86%
- ONT to LAS 78%
- ONT to DFW 78%
- ONT to SMF 86%
- ONT to OAK 87%
- ONT to SJC 86%
- ONT to SFO 69%
- ONT to SLC 91%
- ONT to PDX 88%
- ONT to IAH 85%
Live status: FAA delays and ground stops