Route reliability record
DEN→MKE
Denver to Milwaukee
- Flights
- 2,307
- Period
- September 2025 to August 2026
- Distance
- 896 mi
- Carriers
- 4
This route lands a B+, level with the national rate of 77.3%. About one flight in four arrives 15 minutes late or worse, and those flights are late by about an hour on average. That rests on 2,307 DEN to MKE flights, of which United Airlines flew 663 at 84.9% on time.
Best time to fly DEN to MKE: a 8am–11am departure, ideally on a Tuesday. Flights in that window arrived on time 88.2% of the time and Tuesday flights 80.4%, against 76.7% for the route overall.
The US average over the same twelve months is 77.3%, 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
76.7%
Arrivals under 15 minutes late, of 2,290 completed flights
Avg delay
62 min
Across delayed arrivals only, not all flights
Cancelled
0.52%
National rate is 1.89%
Best carrier
United
84.9% on time across 663 flights
These figures cover 2,307 flights between September 2025 and August 2026. The median arrival is 3 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
Which airline is most reliable on DEN to MKE
The choice of carrier is not cosmetic here. United Airlines arrives on time 84.9% of the time; Southwest Airlines manages 73.0%. Sample sizes sit next to every figure, because a two-point gap across 1,246 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Frontier Airlinesthin sample | 41 | 92.7% | 49 min | 0.00% | A+ |
| United Airlines | 663 | 84.9% | 62 min | 0.00% | B+ |
| Southwest Airlines | 1,246 | 73.0% | 55 min | 0.80% | C+ |
| SkyWest Airlinesthin sample | 357 | 72.6% | 87 min | 0.56% | C+ |
United leads Southwest by 12 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.
Flight by flight
Flights on DEN 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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Best ways to make this trip
The most reliable ways to fly Denver to Milwaukee
Every airline on this route, ranked by how often a scheduled flight actually operated and arrived on time, with its best departure time and most punctual flight number. No nearby airport pair beat these.
| Option | Airline | Success | On time | Cancelled | Best departure | Most punctual flight |
|---|---|---|---|---|---|---|
| 1. DEN → MKEDenver to Milwaukee | United Airlines | 84.9% | 84.9% | 0.00% | 8am–11am, Thu | UA 1836 09:57 |
| 2. DEN → MKEDenver to Milwaukee | Southwest Airlines | 72.4% | 73.0% | 0.80% | 8am–11am, Wed | — |
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.
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 24 points, against 12 points between the best and worst carrier.
- 5am–8am33 flights87.9%
- 8am–11am545 flights88.2%
- 11am–2pm522 flights87.1%
- 2pm–5pm301 flights71.6%
- 5pm–8pm706 flights64.4%
- 8pm–5am200 flights67.7%
Scale runs 55% to 95%.
The 5pm–8pm window is where this operation falls apart: 64.4% on time, against 88.2% for the 8am–11am 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 706 flights scheduled in it.
Explore
Filter DEN 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 DEN to MKE, the best departure window is 8am–11am at 88.2% on time and the worst is 5pm–8pm at 64.4%, a wide gap of 23.8 points. All US flights leaving 8am–11am ran 83.9%.
- 5–8am87.9%
- 8–11am88.2%
- 11am–2pm87.1%
- 2–5pm71.6%
- 5–8pm64.4%
- 8pm–5am67.7%
best all US flightsScale 55% to 95%.
Across the year
When delays peak on this route
This route's year swings by 25 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.
August is the worst month at 62.3% on time, 25 points below October, the best at 87.1%. 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 248 flights.
Across the week, Tuesday is the strongest day at 80.4% on time and Friday the weakest at 73.1%, a spread of 7 points.
Delay causes
Why this route gets delayed
Late-arriving aircraft accounts for 45% of the 33,000 delay minutes carriers reported here, and the remaining four split what is left.
- 45%Late-arriving aircraft
- 35%Carrier
- 15%National Airspace System
- 4%Extreme weather
45% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 33,000 reported delay minutes here, that single category outweighs weather by 10 to one. The split is drawn from 32,912 reported delay minutes.
The largest share of delay minutes, 35%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 12,000 of the 33,000 delay minutes reported here.
Cancellations are rare at 0.52%, below the national 1.89% and low enough to earn the plus on the grade. Roughly one flight in 100 is called off; the risk here is arriving late, not not arriving.
Connections and stage length
What a delay here actually costs
7.6% 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 896 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 runs 78.8% on time across 2,310 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 2,307 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 calendar is the biggest lever here, not the carrier or the hour. October runs 87.1% on time and August 62.3%, a swing of 25 points. If the dates move at all, move them out of August before you think about anything else. 2,290 completed flights over 12 months sit behind that.
Common questions
DEN to MKE questions
How often is DEN to MKE delayed?
About 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 23.3% of the 2,307 flights in this analysis, against 22.7% nationally. Delayed flights are late by about an hour on average.
Which airline is most reliable on DEN to MKE?
United Airlines leads at 84.9% on time across 663 flights. Southwest Airlines is at the other end on 73.0%, 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 DEN to MKE?
The 8am–11am departure window is the strongest at 88.2% on time. The 5pm–8pm window is the weakest at 64.4%, 24 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 August delays on DEN to MKE?
August is the weakest month at 62.3% on time, compared with 87.1% in October. Across the year that is 25 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 DEN — the return legseparate record
- Denver International (DEN) delay statistics
- Milwaukee Mitchell International (MKE) delay statistics
- United Airlines on DEN to MKE84.9%
- Southwest Airlines on DEN to MKE73.0%
- SkyWest Airlines on DEN to MKE72.6%
- DEN to PHX, a related route75.6%
- ORD to MKE, a related route64.3%
- DEN to SLC, a related route78.2%
- Frontier Airlines on-time record92.7%
- United Airlines on-time record84.9%
- Southwest Airlines on-time record73.0%
- Same route, different airline: where the carrier you pick matters most
- Why the first flight of the morning is statistically safest
Direction matters. DEN to MKE and MKE to DEN 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.