Route reliability record
MKE→PHX
Milwaukee to Phoenix
- Flights
- 1,471
- Period
- July 2025 to June 2026
- Distance
- 1,460 mi
- Carriers
- 3
This route lands a B+, about a point better than the national rate of 77.6%. About one flight in five arrives 15 minutes late or worse, and those flights are late by a little over an hour on average. That is a workable record, not a spotless one. That rests on 1,471 MKE to PHX flights, of which Southwest Airlines flew 981 at 79.3% on time.
Best time to fly MKE to PHX: a 8am–11am departure, ideally on a Friday. Flights in that window arrived on time 89.1% of the time and Friday flights 84.3%, against 78.8% 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
78.8%
Arrivals under 15 minutes late, of 1,455 completed flights
Avg delay
71 min
Across delayed arrivals only, not all flights
Cancelled
0.88%
National rate is 1.81%
Best carrier
Southwest
79.3% on time across 981 flights
These figures cover 1,471 flights between July 2025 and June 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.
Carrier by carrier
Which airline is most reliable on MKE to PHX
The two carriers here are closely matched: about 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 | 981 | 79.3% | 54 min | 0.41% | B+ |
| American Airlines | 486 | 77.9% | 103 min | 1.85% | B |
| Frontier Airlinesthin sample | 4 | 50.0% | 55 min | 0.00% | F+ |
No carrier stands out. Southwest tops the table at 79.3%, about a point clear of the bottom, which is inside the range this kind of sample moves year to year.
Best ways to make this trip
The most reliable ways to fly Milwaukee to Phoenix
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 → PHXMilwaukee to Phoenix | Southwest Airlines | 79.0% | 79.3% | 0.41% | 5am–8am, Fri | — |
| 2. MKE → PHXMilwaukee to Phoenix | American Airlines | 76.5% | 77.9% | 1.85% | 2pm–5pm, 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 23 points, against about a point between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am598 flights86.8%
- 8am–11am46 flights89.1%
- 11am–2pm168 flights81.4%
- 2pm–5pm214 flights76.5%
- 5pm–8pm378 flights66.5%
- 8pm–5am67 flights69.2%
Scale runs 60% to 95%. Rows with fewer than 30 flights show a dash.
Book the morning departure. Flights leaving between 8am–11am arrive on time 89.1% of the time, against 66.5% for the evening window. That is 23 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 5am–8am window is the busiest, with 598 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 20 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 68.8% on time, against 89.2% in October. 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. March was the busiest month here, with 165 flights.
Across the week, Friday is the strongest day at 84.3% on time and Sunday the weakest at 74.2%. 10 points is a smaller lever than departure hour, but it is free.
Delay causes
Why this route gets delayed
One category carries most of the weight here. Carrier accounts for 47% of the 22,000 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.
- 47%Carrier
- 38%Late-arriving aircraft
- 14%National Airspace System
- 2%Extreme weather
- 0%Security
38% 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 22,000 reported delay minutes here, that single category outweighs weather by 20 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 21,882 reported delay minutes.
The largest share of delay minutes, 47%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. Unlike weather, that is a management outcome, and it is the category where the gap between two carriers on the same schedule is genuinely earned. It accounts for 10,000 of the 22,000 delay minutes reported here.
Cancellations are rare at 0.88%, below the national 1.81% 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
6.7% of arrivals land an hour or more late, close to the national 8.1%. 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 last a little over an hour, which a normal layover absorbs.
The 1,460 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 is a different operation and performs like one: it runs 73.3% on time across 1,470 flights, 6 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 6 points of difference.
The sample behind these figures is 1,471 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 PHX 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 89.2% on time and December 68.8%, a swing of 20 points. If the dates move at all, move them out of December before you think about anything else. 1,455 completed flights over 12 months sit behind that.
Common questions
MKE to PHX questions
How often is MKE to PHX 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 1,471 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 MKE to PHX?
Southwest Airlines leads at 79.3% on time across 981 flights. American Airlines is at the other end on 77.9%, a gap of about 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 PHX?
The 8am–11am departure window is the strongest at 89.1% on time. The 5pm–8pm window is the weakest at 66.5%, 23 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 PHX?
December is the weakest month at 68.8% on time, compared with 89.2% in October. Across the year that is 20 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
- PHX to MKE — the return legseparate record
- Phoenix Sky Harbor International (PHX) delay statistics
- Southwest Airlines on MKE to PHX79.3%
- American Airlines on MKE to PHX77.9%
- MKE to ORD, a related route67.4%
- DEN to PHX, a related route75.7%
- MKE to DEN, a related route78.1%
- Southwest Airlines on-time record79.3%
- American Airlines on-time record77.9%
- Frontier Airlines on-time record50.0%
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.04 million flight records
Direction matters. MKE to PHX and PHX to MKE 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.