Route profile
ONT→MDW
Flight reliability, delays and best times to fly from Ontario to Chicago, 1,706 miles.
Right now
Aviation weather is not currently a factor.
Aviation weather is not currently a factor.
Route reliability
July 2023 – July 2026
Better than 100% of comparable major US routes (4,598 compared)
Calculated from 1,115 flights. How this is calculated · What counts as on time
ONT → MDW arrives on time 89.1% of the time; the return trip, MDW → ONT, arrives on time 76.9% of the time, a 12.3-point gap between the two directions of the same city pair.
ONT → MDW spends 16.0 minutes on the ground on a 1,706-mile trip: 11.3 minutes from pushback to wheels-up at ONT and 4.7 minutes from touchdown to gate at MDW.
Source: US DOT Bureau of Transportation Statistics · Data covering July 2023 – July 2026
What stands out
This route stays close to typical even on its worst days, a smaller gap than 98% of 4,598 comparable routes.
A typical arrival is 7 min early, and the worst tenth are only 23 minutes worse than that.
Source: FlyerIntel analysis of US DOT BTS data · July 2023 – July 2026 · Ranked against every other route with the same kind of figure and at least 4,598 in the comparison.
What sets this route apart
Where ONT to MDW differs most from similar routes by hour, weekday, month and airline, July 2023 – July 2026.
ONT to MDW is at its best against routes of similar length for flights scheduled at 11 AM: 89.7% arrive on time, 11.6 points ahead of the 78.1% those routes manage at that hour. Against all other routes the gap is 8.7 points.
ONT to MDW holds up on Fridays better than routes of similar length do: 92.5% on time to their 76.2%, a 16.3 points lead. Against all other routes the gap is 16.3 points.
July is kinder to ONT to MDW than to routes of similar length: 83.7% on time against 69.8%, 13.9 points better. Against all other routes the gap is 14 points.
Southwest Airlines does better on ONT to MDW than on its routes of similar length: 89.1% on time here, 75.3% there, 13.8 points apart. Against all other routes the gap is 11.7 points.
ONT to MDW against comparable routes
July 2023 – July 2026| Measure | This route | Compared with | Them | Gap | Flights behind it |
|---|---|---|---|---|---|
| Hour: 11 AM departures | 89.7% | routes of similar length | 78.1% | +11.6 pts | 145 here, 82,671 there |
| Weekday: Friday | 92.5% | routes of similar length | 76.2% | +16.3 pts | 159 here, 205,985 there |
| Month: July | 83.7% | routes of similar length | 69.8% | +13.9 pts | 123 here, 164,531 there |
| Airline: Southwest Airlines | 89.1% | routes of similar length | 75.3% | +13.8 pts | 1,105 here, 273,317 there |
Each comparison pools the flights of other routes, with this route’s own left out. Similar length means within 15% of this route’s 1,706 miles, with at least 5 such routes. A bucket is set against the most comparable group that has enough flights: similar length, then the same origin (at least 3 routes), then all other routes. Hours, weekdays and months appear only where both sides have 120 completed flights, and airlines where both have 600. The gap must be at least 2 points and 2 standard errors, and only the largest gap each way is kept per measure. These are differences in the flights counted, not causes.
When it goes wrong
July 2023 – July 2026
16 min late
against a median of 7 min early
Percentiles over 1,115 operations; cancelled and diverted flights are counted separately.
Will your connection be tight enough?
Layovers at MDW after arriving from ONT.
| Connection time | Chance of missing | Reads as |
|---|---|---|
| 30 min | 30% | Likely to miss |
| 45 min | 10% | Some risk |
| 60 min | 5.1% | Some risk |
| 90 min | 2.2% | Low risk |
| 120 min | 0.8% | Low risk |
This is one leg of a connection. Gate changes and the next flight's own schedule matter too. And a connection can fail before delay is even the question — this route cancels 0.36% of the time and diverts 0.54% of the time, which a late arrival never shows up in.
Chance of missing is the share of 1,105 arrivals on this route that landed later than the connection time less 30 minutes to reach the next gate.
The worst tenth of arrivals on this route land at least 16 minutes late (90th-percentile gate arrival delay), over 1,115 operations.
Any other layover length: connection checker.
Best time to fly
ONT → MDW flights departing 5–9 AM arrived on time 91.5% of the time, against 77.5% for 12–3 PM departures, a gap of 14.0 percentage points.
By departure window
By departure hour
- 12 AM to 5 AM: too few flights to score
- 6 AM: 94.3% on time from 283 flights
- 7 AM: too few flights to score
- 8 AM: 88.3% on time from 129 flights
- 9 AM to 10 AM: too few flights to score
- 11 AM: 89.7% on time from 147 flights
- 12 PM to 10 PM: too few flights to score
- 11 PM: 87.8% on time from 149 flights
Why ONT → MDW runs late
July 2023 – July 2026
crew, maintenance, boarding and fueling, all within the carrier’s control
the inbound aircraft was late, so this flight started late
airspace and airport capacity, including weather-driven flow control
screening or terminal security incidents
Share of the delay minutes US DOT attributed to each cause for ONT → MDW. Only delays of 15 minutes or more are attributed. What the five causes mean
Airlines on this route
Carriers with at least 200 flights, by the airline that operated each one.
| Carrier | Flights | On time | Cancelled | Median delay | Severe |
|---|---|---|---|---|---|
| Southwest Airlines | 1,115 | 89.1% | 0.36% | -7 min | 2.2% |
Other ways to fly Los Angeles to Chicago
Airport pairs in the same two city markets, as the DOT defines them.
| Route | Flights | On time | Cancelled | Median delay | Score |
|---|---|---|---|---|---|
| LAX→ORD Los Angeles to Chicago | 21,167 | 80.9% | 1.29% | -9 min | 67 |
| ONT→MDW this route Ontario to Chicago | 1,115 | 89.1% | 0.36% | -7 min | 93 |
ONT → MDW is the most reliable pairing for this journey at 89.1% on time, against 80.9% for LAX → ORD.
Flying to MDW from the Los Angeles area? Compare ONT, LAX, SNA, BUR for MDW, with the same test for what counts as a real difference.
Weekly and seasonal patterns
By day of week
Friday is historically the most reliable day and Wednesday the least, a gap of 6.3 percentage points.
Reliability over time
July 2023 – July 2026
Over the most recent 12 months (2025-08 to 2026-07), on-time arrivals averaged 90.2% against 88.6% in the 12 months before — improving by 1.6 percentage points.
Data and methodology
Calculated by FlyerIntel from 1,115 ONT → MDW flight records from the US DOT Bureau of Transportation Statistics, covering July 2023 – July 2026. Late means 15 or more minutes past scheduled arrival; cancelled and diverted flights are left out of on-time rates.
Full methodology · Data sources · Report a problem
Related research: How Long a Layover Needs to Be · Two Airlines on One Route · Best Time of Day to Fly From Major US Airports
Analysis last recomputed