Route on-time record
MDW to ONT: most on-time flights and the best time to fly
Chicago (Chicago Midway International Airport) to Ontario (Ontario International Airport). 360 nonstop flights in Jun 2025 to May 2026, 71% arrived within 15 minutes and 1.1% were cancelled. The most reliable flight number was Southwest 3123 at 11:50 AM.
Flying on a specific date? We’ll adjust for the month, the weekday and the forecast.
MDW → ONT
Chicago to Ontario: 360 nonstop flights a year
On time (12 months)
71%
Cancelled
1.1%
avg delay 19 min
Best time to leave
Before 9 AM
85% on time vs 51% 6 to 9 PM
Most reliable airline
Southwest
71% chance on time
Lowest nonstop fare seen in the next two months: $241 (Southwest 3366 on 2026-10-21). 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 3123
11:50 AM → 2:10 PM4h 20m nonstop
Local times, typical schedule. Last flown 2026-04-06.
67%
chance on time
- On time (history)
- 66%
- Cancelled
- 3.0%
- Avg arrival delay
- 17 min
- Arrived on time 66% of the time (32 flights, Jun 2025 to May 2026).
- Cancelled 3.0% of the time (1 of 33).
- Departs inside MDW's trouble window: 50% of its 30 ground stops and delay programs started between 7 AM and 1 PM.
- Short track record (32 flights), so its score leans on the airline's record at this hour.
Limited track record · 32 flights
Find Southwest 3123 fares Opens this date on Aviasales#2 · Southwest 3332
11:00 AM → 1:15 PM4h 15m nonstop
Local times, typical schedule. Last flown 2026-05-31.
65%
chance on time
- On time (history)
- 60%
- Cancelled
- 0.0%
- Avg arrival delay
- 23 min
- Arrived on time 60% of the time (55 flights, Jun 2025 to May 2026).
- Never cancelled in 55 scheduled flights.
- Departs inside MDW's trouble window: 50% of its 30 ground stops and delay programs started between 7 AM and 1 PM.
- Short track record (55 flights), so its score leans on the airline's record at this hour.
Limited track record · 55 flights
Find Southwest 3332 fares Opens this date on Aviasales
Airlines on this route
Season-adjusted chance of operating and arriving on time.
- Southwest Airlines71%
360 flights · 71% on time as flown · 1.1% cancel
On time by departure time
All airlines, scheduled local departure, Jun 2025 to May 2026.
- Before 9 AM85%
114 flights · avg delay 8 min
- 9 AM to noon68%
88 flights · avg delay 23 min
- Noon to 3 PM83%
47 flights · avg delay 17 min
- 3 to 6 PM62%
50 flights · avg delay 26 min
- 6 to 9 PM51%
44 flights · avg delay 35 min
Best day: Thursday (83%). Worst: Sunday (69%).
Smarter routing
Nearby airports that run more on time
MDW → BUR 77% chance on time
Chicago Midway International Airport to Hollywood Burbank/Bob Hope Airport · 322 flights a year · 44 mi from your airports · yours: 71%
ORD → SNA 75% chance on time
Chicago O'Hare International Airport to John Wayne Orange County International Airport · 2,238 flights a year · 45 mi from your airports · yours: 71%
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)42%
- Late-arriving aircraft41%
- Air traffic control and airport volume12%
- Severe weather5%
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
MDW to ONT questions
- What time of day is best to fly MDW to ONT?
- Before 9 AM: 85% of flights arrived on time, against 51% 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 MDW to ONT?
- Southwest, with a season-adjusted 71% chance of operating and arriving on time over 360 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 MDW to ONT?
- May (65% on time); the best was November (90%), 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 MDW
- ONT to MDW (return)
- MDW to ATL 80%
- MDW to PHX 76%
- MDW to MCO 77%
- MDW to MSP 78%
- MDW to LAS 77%
- MDW to DEN 73%
- MDW to LGA 69%
- MDW to DAL 77%
- MDW to DCA 69%
- MDW to MCI 79%
- MDW to BNA 80%
- MDW to BWI 79%
Live status: FAA delays and ground stops