Carrier route record
WNDCA→MKE
Southwest Airlines · Washington to Milwaukee
- Flights
- 681
- Period
- September 2025 to August 2026
- Share of route
- 51%
- Carriers
- 3
Historical statistics for September 2025 to August 2026, not live status. For today’s flights, check with Southwest Airlines.
Southwest on DCA to MKE lands a B, 5 points better than the national rate of 77.3%. About one flight in six arrives 15 minutes late or worse, and those flights are late by about an hour on average. That rests on 681 flights, with a median arrival 7 minutes early.
Set against the rest of the country, Southwest's DCA to MKE record is 5 points better than the US average of 77.3%. That gap is worth roughly 52 fewer late arrivals for every thousand flights.
Key figures
On time
82.5%
Arrivals under 15 minutes late, of 667 completed flights
Avg delay
59 min
Across delayed arrivals only, not all flights
Cancelled
2.06%
National rate is 1.89%
Whole route
76.3%
Every carrier on DCA to MKE, 1,346 flights
These figures cover 681 flights between September 2025 and August 2026. The median arrival is 7 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.
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Carrier by carrier
Southwest against every carrier on DCA to MKE
Southwest flew 681 of the 1,346 flights on DCA to MKE, most of the route. Its 82.5% on time is 6 points better than the route as a whole, which runs 76.3%. Ranked by on-time rate it is number two of three carriers on the route, where the range runs from Republic at 83.3% to PSA at 69.3%. One of those carriers flew fewer than 365 flights here, so treat their positions as rough.
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 | 7 | 83.3% | 81 min | 14.29% | B− |
| Southwest Airlines (this page) | 681 | 82.5% | 59 min | 2.06% | B |
| PSA Airlines | 658 | 69.3% | 76 min | 8.51% | C− |
Timetable by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.
Departure window
When Southwest runs best on this route
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 27 points, against half a point between the best and worst carrier.
- 5am–8am206 flights96.5%
- 8am–11am119 flights92.3%
- 11am–2pm25 flights—
- 2pm–5pm330 flights69.9%
- 5pm–8pm1 flights—
- 8pm–5am—
Scale runs 60% to 100%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 96.5% of the time, against 69.9% for the afternoon window. That is 27 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 2pm–5pm window is the busiest, with 330 flights scheduled in it.
Across the year
Southwest on DCA to MKE through the year
July is the worst month at 69.1% on time, 25 points below January, the best at 94.4%. Summer afternoon convection and peak-season schedules land on the same weeks every year, so this is a pattern you can book around rather than a run of bad luck. June was the busiest month here, with 60 flights.
Across the week, Tuesday is the strongest day at 89.1% on time and Thursday the weakest at 73.0%, a spread of 16 points.
Arrival by arrival
How late Southwest on DCA to MKE runs when it is late
Southwest on DCA to MKE often beats the schedule: 178 of 667 completed flights, 27%, arrived 15 minutes or more early. The 117 late arrivals split 48 under half an hour, 31 between 30 and 60 minutes, and 38 an hour or more.
- 15+ min early178 flights26.7%
- Within 15 min372 flights55.8%
- 15–29 min late48 flights7.2%
- 30–59 min late31 flights4.6%
- 1–2 hours late26 flights3.9%
- 2+ hours late12 flights1.8%
Scale runs 0% to 100%.
Share of 667 completed flights by arrival against schedule.
A late pushback is often recovered here: of 142 departures that left 15 minutes late or more, 46 still arrived on time. 21 flights left on time and still arrived late.
The worst days
Worst days for Southwest on DCA to MKE
The latest arrival of the period was on 11 June 2026, 5 hours 33 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). The same cause led on three of the five worst days.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 11 June 2026 | 5 hours 33 minutes | Carrier |
| 16 February 2026 | 5 hours 23 minutes | Late-arriving aircraft |
| 16 August 2026 | 4 hours 36 minutes | Carrier |
| 19 September 2025 | 3 hours 44 minutes | Late-arriving aircraft |
| 23 August 2026 | 3 hours 21 minutes | Carrier |
Delay causes
Why Southwest runs late on this route
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 6,938 reported delay minutes.
- 42%Late-arriving aircraft
- 33%Carrier
- 24%National Airspace System
- 2%Extreme weather
42% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 6,938 reported delay minutes here, that single category outweighs weather by 22 to one. The split is drawn from 6,938 reported delay minutes.
The practical consequence: the 5am–8am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 96.5% on time here.
Cancellations sit at 2.06% against a national 1.89%, which is ordinary. Diversions add another 0.00%.
Connections and stage length
What a delay here costs
5.7% of arrivals land an hour or more late, close to the national 8.3%, so a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last about an hour, which a normal layover absorbs.
The 634 miles between these two airports put this in the middle of the US network, around two and a half to three hours of block time. That is enough cruise to absorb a ten-minute late pushback and not enough to absorb thirty.
The return leg is a different operation and performs like one: it runs 73.3% on time across 680 flights, 9 points below 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 9 points of difference.
One caution: this is a thin sample. 681 flights over twelve months is enough to clear this site's floor but not enough to pin the rate down tightly, and a single bad week moves it by more than a point. Treat the grade as a rough reading.
What to do with this
Booking Southwest on DCA to MKE
Put together: treat all of this as provisional. 681 flights over twelve months is enough to clear this site's floor and not enough to be confident to better than a couple of points. The 82.5% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 667 completed flights over 12 months sit behind that.
Related
Where to go next
- DCA to MKE, every carrier
- Southwest on MKE to DCA, the return leg
- PSA Airlines on DCA to MKE69.3%
- Southwest Airlines network-wide record
- Ronald Reagan Washington National (DCA) delay statistics
- Milwaukee Mitchell International (MKE) delay statistics
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.05 million flight records
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.