Carrier performance at one airport
WN→MKE
Southwest Airlines at Milwaukee Mitchell International
- Departures
- 9,891
- Period
- June 2025 to May 2026
- Routes
- 16
- Rank here
- #2 of 8
Southwest Airlines at Milwaukee lands a B, 3 points better than the national rate of 77.4%. About one flight in five arrive 15 minutes late or worse, and those flights are late by about an hour on average. That is a workable record, not a spotless one. That rests on 9,891 flights, of which Delta Air Lines flew 3,846 at 86.7% on time.
Measured against the airport rather than the country, Southwest Airlines runs 3 points ahead of the 78.0% weighted average across all carriers at MKE. That is the comparison worth making: every operator here works the same runways, the same airspace and the same weather.
Key figures
On time
80.6%
9,760 completed departures
Avg delay
56 min
Across delayed flights only
Cancelled
1.00%
At MKE, this carrier only
Rank here
#2
Of 8 carriers clearing the floor at MKE
These figures cover 9,891 flights between June 2025 and May 2026. The median arrival is 5 minutes early, which is the part an average hides: most flights here are fine, and the on-time rate is decided by a tail of badly late ones. On-time means under 15 minutes late, the DOT's own threshold.
Against the competition
Every carrier at MKE, ranked
The choice of carrier is not cosmetic here. Delta Air Lines arrives on time 86.7% of the time; SkyWest Airlines manages 70.5%. Sample sizes sit next to every figure, because a two-point gap across 7,040 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Delta Air Lines | 3,846 | 86.7% | 90 min | 1.69% | A |
| Southwest Airlines (this page) | 9,891 | 80.6% | 56 min | 1.00% | B |
| Alaska Airlines | 510 | 79.8% | 41 min | 0.59% | B+ |
| Republic Airways | 2,337 | 77.3% | 81 min | 5.26% | B− |
| American Airlines | 2,340 | 77.0% | 117 min | 2.52% | B |
| United Airlines | 793 | 76.5% | 65 min | 0.13% | B+ |
| PSA Airlines | 1,258 | 76.0% | 126 min | 4.61% | B− |
| SkyWest Airlines | 7,040 | 70.5% | 95 min | 3.03% | C− |
Republic Airways cancels 5.3% of what it schedules here, the highest in the table. A cancelled flight never appears in an on-time rate, so read that column alongside the punctuality one rather than after it.
Route by route
Where Southwest Airlines flies from MKE
Southwest Airlines operates 16 routes out of MKE with enough volume to report. Route records inside one carrier at one airport still spread widely, because a short shuttle and a transcontinental have very different exposure to a late inbound.
| Route | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| MKE to DEN · Denver | 1,261 | 79.8% | 60 min | 0.79% | B+ |
| MKE to MCO · Orlando | 1,103 | 75.6% | 52 min | 0.63% | B+ |
| MKE to LAS · Las Vegas | 1,003 | 81.8% | 55 min | 0.90% | B+ |
| MKE to PHX · Phoenix | 996 | 80.3% | 56 min | 0.40% | B+ |
| MKE to BNA · Nashville | 968 | 82.5% | 51 min | 1.55% | B |
| MKE to BWI · Baltimore | 825 | 84.6% | 66 min | 1.94% | B |
| MKE to STL · St. Louis | 683 | 89.5% | 61 min | 0.88% | A+ |
| MKE to DCA · Washington | 683 | 74.6% | 58 min | 1.76% | C |
| MKE to TPA · Tampa | 461 | 84.8% | 59 min | 1.30% | B |
| MKE to RSW · Fort Myers | 436 | 79.8% | 60 min | 0.69% | B+ |
| MKE to DAL · Dallas | 408 | 79.0% | 63 min | 0.25% | B+ |
| MKE to MCI · Kansas Citythin sample | 350 | 84.5% | 42 min | 0.57% | B+ |
| MKE to AUS · Austinthin sample | 288 | 83.5% | 55 min | 0.69% | B+ |
| MKE to MDW · Chicagothin sample | 176 | 71.6% | 58 min | 2.84% | C |
| MKE to SAN · San Diegothin sample | 142 | 69.5% | 45 min | 0.00% | C+ |
| MKE to FLL · Fort Lauderdalethin sample | 85 | 70.2% | 46 min | 1.18% | C |
Departure window
Best time of day for this operation
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 31 points, against 16 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am2,890 flights92.8%
- 8am–11am1,227 flights88.5%
- 11am–2pm1,821 flights81.9%
- 2pm–5pm1,875 flights73.5%
- 5pm–8pm1,711 flights64.5%
- 8pm–5am367 flights61.8%
Scale runs 55% to 100%. Rows with fewer than 30 flights show a dash.
The 8pm–5am window is where this operation falls apart: 61.8% on time, against 92.8% 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.
Across the year
Seasonal pattern
December is the weak month at 74.4% on time, against 87.1% 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.
Delay causes
What holds this operation up
- 46%Late-arriving aircraft
- 28%National Airspace System
- 24%Carrier
- 2%Extreme weather
- 0%Security
46% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. That is a cascade, and cascades start small and grow through the day. Across 106,000 reported delay minutes here, that single category outweighs weather by 24 to one. It is the strongest argument for booking the first departure of the morning, when the aircraft has been sitting at the gate overnight with nothing to inherit.
Cancellations sit at 1.00% against a national 1.80%, which is ordinary. Diversions add another 0.32%.
5.5% of arrivals land an hour or more late, close to the national 8.2%. That is the figure that decides a connection, and it says a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route are the about an hour kind, which a normal layover absorbs.
The sample behind these figures is 9,891 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.
Put together: the calendar is the biggest lever here, not the carrier or the hour. September runs 87.1% on time and December 74.4%, a swing of 13 points. If the dates move at all, move them out of December before you think about anything else.
Common questions
Southwest Airlines at MKE
How often is Southwest Airlines at MKE delayed?
About one flight in five arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 19.4% of the 9,891 flights in this analysis, against 22.6% nationally. Delayed flights are late by about an hour on average.
Which airline is most reliable on Southwest Airlines at MKE?
Delta Air Lines leads at 86.7% on time across 3,846 flights. SkyWest Airlines is at the other end on 70.5%, a gap of 16 points. Sample size matters as much as the percentage: a rate built from a few hundred flights moves around far more than one built from ten thousand.
What time of day has the fewest delays on Southwest Airlines at MKE?
The 5am–8am departure window is the strongest at 92.8% on time. The 8pm–5am window is the weakest at 61.8%, 31 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 Southwest Airlines at MKE?
December is the weakest month at 74.4% on time, compared with 87.1% in September. Across the year that is 13 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
Source: US DOT Bureau of Transportation Statistics, on-time performance data, June 2025 to May 2026. Updated monthly. How this data is collected.