MDW to ONT flight delays & on-time performance
Nonstop flights from Chicago Midway International Airport to Ontario International Airport · 1,706 miles · Aug 2025 – Jul 2026
No FAA-reported ground stops or delays at MDW or ONT right now. Individual flights can still be delayed by the airline; check with your airline for your flight.
Key facts
- Flights from Chicago (MDW) to Ontario (ONT) arrived on time 70% of the time in Aug 2025 – Jul 2026, worse than the 78% national average.
- 1.1% were cancelled, and 7% arrived an hour or more late.
- Southwest Airlines is the only airline reporting nonstop flights on this route.
- Departures scheduled around 7am did best (88% on time); around 9pm did worst (44%).
- Wednesday was the most reliable day to fly (79% on time) and Sunday the least (59%).
- The largest source of delay minutes was airline (crew, maintenance, cleaning, fueling) (48%).
Which airline is most on time from MDW to ONT?
Ranked by on-time arrival rate. Regional airlines fly under their partner's brand (e.g. SkyWest for Delta Connection or United Express).
| Airline | On time | Cancelled | Avg delay | 1 hr+ late | Flights |
|---|---|---|---|---|---|
| Southwest Airlines | 70% | 1.1% | 17 min | 7.3% | 360 |
Best time of day to fly
On-time arrival rate by scheduled departure hour (local time).
- 7am88%17 flights
- 8am84%96 flights
- 10am73%22 flights
- 11am67%96 flights
- 12pm88%16 flights
- 1pm64%14 flights
- 3pm48%25 flights
- 5pm84%19 flights
- 8pm58%25 flights
- 9pm44%17 flights
Best day of the week
On-time arrival rate by day of departure.
- Monday70%3.8% cancelled
- Tuesday73%0.0% cancelled
- Wednesday79%0.0% cancelled
- Thursday69%0.0% cancelled
- Friday72%0.0% cancelled
- Saturday70%2.1% cancelled
- Sunday59%1.9% cancelled
On-time trend by month
Why flights are late
Share of delay minutes by cause, as reported by airlines to the DOT.
- Airline (crew, maintenance, cleaning, fueling)48%
- Late-arriving aircraft31%
- Air traffic control & airport congestion14%
- Extreme weather6%
- Security0%
Why flights are cancelled
Share of cancellations by reason.
- Extreme weather75%
- Air traffic control & airport congestion25%
- Airline (crew, maintenance, cleaning, fueling)0%
- Security0%
MDW to ONT: common questions
- How often are MDW to ONT flights on time?
- 70% of flights arrived less than 15 minutes late in Aug 2025 – Jul 2026, compared with 78% for all US flights.
- How often are flights from Chicago to Ontario cancelled?
- 1.1% of scheduled flights were cancelled (4 of 360).
- How long are typical delays?
- Across all flights the average arrival delay was 17 min (early arrivals count as zero). Flights that were late arrived 52 min behind schedule on average, and 7.3% of flights were an hour or more late.
- How long is taxi time at MDW?
- Flights on this route spent 16 min taxiing from the gate to takeoff on average.
Related routes
Return trip: ONT to MDW — 90% on time
More flights from Chicago
Data: U.S. DOT Bureau of Transportation Statistics, Aug 2025 – Jul 2026 (12 months). Latest month published by BTS: July 2026. Route: MDW → ONT, nonstop flights by US airlines that report to the DOT. How we calculate this.