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DelayAtlas

Route reliability record

DCAMKE

Washington to Milwaukee

Flights
1,349
Period
July 2025 to June 2026
Distance
634 mi
Carriers
3
B−GRADE

This route carries a cancellation problem, not just a delay problem: 4.3% of scheduled flights never operate, against 1.8% nationally. Of the ones that do fly, close to three flights in four arrive on time, worth a B− overall. The punctuality figure counts only flights that actually departed, so it flatters an operation that cancels this often. That rests on 1,349 DCA to MKE flights, of which Southwest Airlines flew 683 at 82.8% on time.

Best time to fly DCA to MKE: a 5am–8am departure, ideally on a Saturday. Flights in that window arrived on time 95.4% of the time and Saturday flights 81.2%, against 77.3% for the route overall.

The US average over the same twelve months is 77.6%, so there is little to separate this route from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.

Key figures

On time

77.3%

Arrivals under 15 minutes late, of 1,288 completed flights

Avg delay

72 min

Across delayed arrivals only, not all flights

Cancelled

4.30%

National rate is 1.81%

Best carrier

Southwest

82.8% on time across 683 flights

These figures cover 1,349 flights between July 2025 and June 2026. Beyond the headline rate, 9.1% of arrivals land a full hour or more behind schedule. That is the number that wrecks a connection, and it is not visible in an on-time percentage alone.

Carrier by carrier

Which airline is most reliable on DCA to MKE

The choice of carrier is not cosmetic here. Southwest Airlines arrives on time 82.8% of the time; PSA Airlines manages 71.3%. Sample sizes sit next to every figure, because a two-point gap across 659 flights means less than a ten-point one.

On-time performance by carrier on DCA to MKE
AirlineFlightsOn timeAvg delayCancelledGrade
Republic Airwaysthin sample783.3%81 min14.29%B−
Southwest Airlines68382.8%64 min1.46%B
PSA Airlines65971.3%77 min7.13%C−

PSA Airlines cancels 7.1% 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.

Flight by flight

Flights on DCA 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.

Best ways to make this trip

The most reliable ways to fly Washington to Milwaukee

Every airline on this route and on the routes between nearby airports, ranked by how often a scheduled flight actually operated and arrived on time. 1 of the top 3 use a different airport at one end.

Most reliable ways to fly from DCA to MKE
OptionAirlineSuccessOn timeCancelledBest departureMost punctual flight
1. DCAMKEWashington to MilwaukeeSouthwest Airlines81.6%82.8%1.46%5am–8am, Tue
2. BWIMKEBaltimore to MilwaukeeSouthwest Airlines74.9%76.1%1.57%8am–11am, Tue (route)
3. DCAMKEWashington to MilwaukeePSA Airlines66.2%71.3%7.13%8am–11am, SatOH 5656 22:25

Success is the share of scheduled flights that operated and arrived less than 15 minutes late, so a cancelled flight counts against it. “(route)” means the best time comes from every carrier on the route rather than this airline alone.

Plan this trip by month, day and time

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 28 points, against 12 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

  • 5am–8am178 flights95.4%
  • 8am–11am227 flights87.8%
  • 11am–2pm252 flights76.2%
  • 2pm–5pm339 flights70.7%
  • 5pm–8pm14 flights
  • 8pm–5am339 flights67.9%

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 95.4% of the time, against 67.9% for the overnight window. That is 28 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 339 flights scheduled in it.

Across the year

When delays peak on this route

This route's year swings by 22 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.

On-time rate by calendar month86J78F73M78A82M74J65J80A83S84O78N67D
Darker means more delays. Figures are on-time percentages.January best, July worst

July is the worst month at 64.8% on time, 22 points below January, the best at 86.4%. 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. July was the busiest month here, with 120 flights.

Across the week, Saturday is the strongest day at 81.2% on time and Thursday the weakest at 72.0%. 9 points is a smaller lever than departure hour, but it is free.

On-time rate by day of the week78.0Mon80.7Tue79.1Wed72.0Thu75.8Fri81.2Sat75.8Sun
Monday: 78.0 percent on time. Tuesday: 80.7 percent on time. Wednesday: 79.1 percent on time. Thursday: 72.0 percent on time. Friday: 75.8 percent on time. Saturday: 81.2 percent on time. Sunday: 75.8 percent on time

Delay causes

Why this route gets delayed

One category carries most of the weight here. Late-arriving aircraft accounts for 49% of the 21,000 delay minutes carriers reported, and the remaining four split what is left. The split is by minutes rather than by flights, so a few very long delays count for as much as many short ones.

  • Late-arriving aircraft
    49%
  • Carrier
    31%
  • National Airspace System
    13%
  • Extreme weather
    7%

49% 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 21,000 reported delay minutes here, that single category outweighs weather by 7 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. The split is drawn from 20,920 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 95.4% on time here.

Cancellations run at 4.30%, against 1.81% nationally. That is about one flight in 25 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

For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 9.1% of arrivals land a full hour or more behind schedule, against 8.1% nationally. A 45-minute layover does not survive that, and no amount of walking quickly changes it. Ninety minutes is the honest minimum here, and two hours if the onward flight is on a separate ticket.

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. It is also long enough that the aircraft usually flies three or four legs a day rather than six, which slows how fast delay compounds.

The return leg runs 75.4% on time across 1,349 flights, within 2 points of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.

The sample behind these figures is 1,349 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 4.30% cancellation rate. A late arrival costs you a little over an hour; 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. 1,288 completed flights over 12 months sit behind that.

Common questions

DCA to MKE questions

How often is DCA to MKE delayed?

Roughly one flight in four arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 22.7% of the 1,349 flights in this analysis, against 22.4% nationally. Delayed flights are late by a little over an hour on average.

Which airline is most reliable on DCA to MKE?

Southwest Airlines leads at 82.8% on time across 683 flights. PSA Airlines is at the other end on 71.3%, a gap of 12 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 DCA to MKE?

The 5am–8am departure window is the strongest at 95.4% on time. The 8pm–5am window is the weakest at 67.9%, 28 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 July delays on DCA to MKE?

July is the weakest month at 64.8% on time, compared with 86.4% in January. Across the year that is 22 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

Direction matters. DCA to MKE and MKE to DCA 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, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.