Route reliability record
MKE→DEN
Milwaukee to Denver
- Flights
- 2,310
- Period
- September 2025 to August 2026
- Distance
- 896 mi
- Carriers
- 4
This route lands a B+, 2 points better than the national rate of 77.3%. About one flight in five arrives 15 minutes late or worse, and those flights are late by about an hour on average. That rests on 2,310 MKE to DEN flights, of which Southwest Airlines flew 1,248 at 78.9% on time.
Best time to fly MKE to DEN: a 5am–8am departure, ideally on a Saturday. Flights in that window arrived on time 96.9% of the time and Saturday flights 81.9%, against 78.8% 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
78.8%
Arrivals under 15 minutes late, of 2,294 completed flights
Avg delay
57 min
Across delayed arrivals only, not all flights
Cancelled
0.43%
National rate is 1.89%
Best carrier
Southwest
78.9% on time across 1,248 flights
These figures cover 2,310 flights between September 2025 and August 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.
Fare search by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.
Carrier by carrier
Which airline is most reliable on MKE to DEN
The two carriers here are closely matched: half a point separate the best from the worst. At that spread, schedule and price are better tie-breakers than reliability. Sample sizes are shown so you can see which rows are worth weighing.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Southwest Airlines | 1,248 | 78.9% | 56 min | 0.64% | B+ |
| SkyWest Airlinesthin sample | 357 | 78.9% | 53 min | 0.28% | B+ |
| United Airlines | 664 | 78.5% | 60 min | 0.15% | B+ |
| Frontier Airlinesthin sample | 41 | 78.0% | 70 min | 0.00% | B+ |
No carrier stands out. Southwest tops the table at 78.9%, half a point clear of the bottom, which is inside the range this kind of sample moves year to year.
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.
Best ways to make this trip
The most reliable ways to fly Milwaukee to Denver
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. MKE → DENMilwaukee to Denver | Southwest Airlines | 78.4% | 78.9% | 0.64% | 5am–8am, Fri | — |
| 2. MKE → DENMilwaukee to Denver | United Airlines | 78.4% | 78.5% | 0.15% | 2pm–5pm, Thu | — |
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 38 points, against half a point between the best and worst carrier.
- 5am–8am393 flights96.9%
- 8am–11am656 flights83.3%
- 11am–2pm219 flights78.5%
- 2pm–5pm504 flights77.4%
- 5pm–8pm460 flights61.7%
- 8pm–5am78 flights59.0%
Scale runs 50% to 100%.
The 8pm–5am window is where this operation falls apart: 59.0% on time, against 96.9% 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 8am–11am window is the busiest, with 656 flights scheduled in it.
Explore
Filter MKE to DEN 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 MKE to DEN, the best departure window is 5am–8am at 96.9% on time and the worst is 8pm–5am at 59.0%, a wide gap of 37.9 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am96.9%
- 8–11am83.3%
- 11am–2pm78.5%
- 2–5pm77.4%
- 5–8pm61.7%
- 8pm–5am59.0%
best all US flightsScale 50% to 100%.
Across the year
When delays peak on this route
This route's year swings by 19 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 67.9% on time, against 86.8% in February. 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. July was the busiest month here, with 248 flights.
Across the week, Saturday is the strongest day at 81.9% on time and Monday the weakest at 76.5%, a spread of 5 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 28,000 reported delay minutes.
- 35%National Airspace System
- 32%Late-arriving aircraft
- 29%Carrier
- 5%Extreme weather
35% of delay minutes are charged to the National Airspace System: air traffic volume, runway configuration, ground stops. No carrier can price its way out of that, which is why airport choice moves the number here more than carrier choice does. That is 9,594 minutes out of 28,000, against a national NAS share of 21%. The split is drawn from 27,585 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 96.9% on time here.
Cancellations are rare at 0.43%, 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
6.3% 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 76.7% on time across 2,307 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 2,310 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 DEN 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. February runs 86.8% on time and December 67.9%, a swing of 19 points. If the dates move at all, move them out of December before you think about anything else. 2,294 completed flights over 12 months sit behind that.
Common questions
MKE to DEN questions
How often is MKE to DEN delayed?
About one flight in five arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 21.2% of the 2,310 flights in this analysis, against 22.7% nationally. Delayed flights are late by about an hour on average.
Which airline is most reliable on MKE to DEN?
Southwest Airlines leads at 78.9% on time across 1,248 flights. United Airlines is at the other end on 78.5%, a gap of half a point. 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 MKE to DEN?
The 5am–8am departure window is the strongest at 96.9% on time. The 8pm–5am window is the weakest at 59.0%, 38 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 MKE to DEN?
December is the weakest month at 67.9% on time, compared with 86.8% in February. Across the year that is 19 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
- DEN to MKE — the return legseparate record
- Milwaukee Mitchell International (MKE) delay statistics
- Denver International (DEN) delay statistics
- Southwest Airlines on MKE to DEN78.9%
- SkyWest Airlines on MKE to DEN78.9%
- United Airlines on MKE to DEN78.5%
- MKE to ORD, a related route68.4%
- PHX to DEN, a related route76.7%
- MKE to ATL, a related route88.5%
- Southwest Airlines on-time record78.9%
- SkyWest Airlines on-time record78.9%
- United Airlines on-time record78.5%
- The best time of day to fly, according to 7.05 million flight records
- Worst months to fly in the US, ranked by the data
Direction matters. MKE to DEN and DEN to MKE are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
Embed MKE to DEN’s on-time badge on your site
Paste this into a web page. The badge shows the current on-time rate, cancellation rate and grade, and updates every month. Preview it, or build a badge for another route or airport.
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.