Route reliability record
ORD→MKE
Chicago to Milwaukee
- Flights
- 5,344
- Period
- September 2025 to August 2026
- Distance
- 67 mi
- Carriers
- 4
This route carries a cancellation problem, not just a delay problem: 4.7% of scheduled flights never operate, against 1.9% nationally. Of the ones that do fly, about two flights in three arrive on time, worth a D− overall. The punctuality figure counts only flights that actually departed, so it flatters an operation that cancels this often. That rests on 5,344 ORD to MKE flights, with a median arrival 1 minute late.
Best time to fly ORD to MKE: a 5am–8am departure, ideally on a Tuesday. Flights in that window arrived on time 73.4% of the time and Tuesday flights 70.4%, against 64.3% for the route overall.
The national on-time rate over the same period is 77.3%, so this route runs 13 points behind the country as a whole. Across a thousand flights that is about 130 extra late arrivals.
Key figures
On time
64.3%
Arrivals under 15 minutes late, of 5,091 completed flights
Avg delay
92 min
Across delayed arrivals only, not all flights
Cancelled
4.68%
National rate is 1.89%
Best carrier
SkyWest
63.9% on time across 5,047 flights
These figures cover 5,344 flights between September 2025 and August 2026. Beyond the headline rate, 17.3% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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Carrier by carrier
Which airline is most reliable on ORD to MKE
Only one carrier clears this site's 365-flight floor here, so there is no comparison to draw. The table below is the full picture.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Republic Airwaysthin sample | 115 | 80.4% | 63 min | 6.96% | B− |
| PSA Airlinesthin sample | 26 | 72.7% | 312 min | 15.38% | C− |
| Envoy Airthin sample | 156 | 65.8% | 68 min | 4.49% | C− |
| SkyWest Airlines | 5,047 | 63.9% | 92 min | 4.58% | D− |
Flight by flight
Flights on ORD to MKE
The flight numbers below flew this route at least 250 times in the period, busiest first. Each has its own record, with its schedule and delay causes.
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Departure window
The best time of day to leave
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 17 points, against half a point between the best and worst carrier.
- 5am–8am304 flights73.4%
- 8am–11am795 flights72.2%
- 11am–2pm766 flights68.9%
- 2pm–5pm881 flights62.4%
- 5pm–8pm1,390 flights56.6%
- 8pm–5am1,208 flights64.0%
Scale runs 50% to 80%.
The 5pm–8pm window is where this operation falls apart: 56.6% on time, against 73.4% for the 5am–8am slot. By evening the aircraft flying these rotations have absorbed a full day of small delays and there is no slack left to recover in. The 5pm–8pm window is the busiest, with 1,390 flights scheduled in it.
Explore
Filter ORD to MKE by airline, time, month and day
Pick a breakdown and a carrier. The dashed mark on each row is the same slice for every US flight.
On ORD to MKE, the best departure window is 5am–8am at 73.4% on time and the worst is 5pm–8pm at 56.6%, a wide gap of 16.8 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am73.4%
- 8–11am72.2%
- 11am–2pm68.9%
- 2–5pm62.4%
- 5–8pm56.6%
- 8pm–5am64.0%
best all US flightsScale 50% to 95%.
Across the year
When delays peak on this route
This route's year swings by 20 points from best month to worst, which is wide. An annual average tells you very little about the week you are actually flying, so read the strip rather than the headline if your dates are fixed.
December is the weak month at 53.1% on time, against 73.3% in September. Winter delays cluster: a single storm system can account for most of a month's shortfall, so an average December hides both very good weeks and genuinely unflyable days. May was the busiest month here, with 517 flights.
Across the week, Tuesday is the strongest day at 70.4% on time and Sunday the weakest at 57.4%, a spread of 13 points.
Delay causes
Why this route gets delayed
Carriers report a reason for every delay minute they cause, in five DOT categories. The split below is by minutes, not by number of flights, so a handful of very long weather delays weighs as much as many short ones. It covers 167,000 reported delay minutes.
- 36%Carrier
- 30%Late-arriving aircraft
- 17%National Airspace System
- 16%Extreme weather
Extreme weather accounts for 16% of delay minutes, well above the single-digit share typical across the system. Weather delays are lumpy: they arrive as whole bad days rather than as a steady drag, so the monthly strip above is the more useful view of the risk. The national share is 6%, so this operation carries roughly 2.6 times the usual weather exposure. The split is drawn from 166,541 reported delay minutes.
The largest share of delay minutes, 36%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 61,000 of the 167,000 delay minutes reported here.
Cancellations run at 4.68%, against 1.89% nationally. That is about one flight in twenty cancelled outright. A cancelled flight is invisible in every on-time figure on this page, so the punctuality numbers above describe only the flights that actually operated.
Connections and stage length
What a delay here actually costs
17.3% of arrivals land a full hour or more behind schedule, against 8.3% nationally. Ninety minutes is the honest minimum for a connection here, and two hours if the onward flight is on a separate ticket.
At 67 miles this is a short hop, and stage length matters more than it looks. A flight this short spends under two hours in the air, which leaves almost nothing to claw back a late pushback with. Delay here is decided on the ground, in the turn, which is why the 5am–8am window matters as much as it does.
The return leg is a different operation and performs like one: it runs 68.4% on time across 5,344 flights, 4 points above this direction. Departure banks, aircraft rotations and the congestion at each end all differ, so scoring the two directions together would average away a real 4 points of difference.
The sample behind these figures is 5,344 flights, enough that the headline rate is stable to within roughly a point. The hour-block and month splits divide that further, so read the thinner bars with more caution than the headline.
Work out the risk of missing a connection in MKE after this flight
What to do with this
Booking this route
Put together: the delay figures matter less here than the 4.68% cancellation rate. A late arrival costs you an hour and a half; a cancelled flight costs you the day. Book the 5am–8am departure so there is still a schedule behind you if it goes wrong, and treat a same-day connection as optimistic. 5,091 completed flights over 12 months sit behind that.
Common questions
ORD to MKE questions
How often is ORD to MKE delayed?
About one flight in three arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 35.7% of the 5,344 flights in this analysis, against 22.7% nationally. Delayed flights are late by an hour and a half on average.
How reliable is ORD to MKE compared with the rest of the country?
64.3% of flights arrive on time here against a national 77.3%, a difference of 13 points against it. That is worth a D− on this site's grading scale.
What time of day has the fewest delays on ORD to MKE?
The 5am–8am departure window is the strongest at 73.4% on time. The 5pm–8pm window is the weakest at 56.6%, 17 points behind. Later departures inherit delays from earlier flights the same aircraft has already flown, which is why the curve slopes the way it does.
How bad are December delays on ORD to MKE?
December is the weakest month at 53.1% on time, compared with 73.3% in September. Across the year that is 20 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.
Related
Where to go next
- MKE to ORD — the return legseparate record
- Chicago O'Hare International (ORD) delay statistics
- Milwaukee Mitchell International (MKE) delay statistics
- Republic Airways on ORD to MKE80.4%
- Envoy Air on ORD to MKE65.8%
- SkyWest Airlines on ORD to MKE63.9%
- ORD to LGA, a related route66.6%
- DEN to MKE, a related route76.7%
- ORD to BOS, a related route66.6%
- Republic Airways on-time record80.4%
- PSA Airlines on-time record72.7%
- Envoy Air on-time record65.8%
- The US routes with the most cancellations
- What a cancellation rate actually tells you (and what it hides)
Direction matters. ORD to MKE and MKE to ORD are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
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Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.