Route reliability record
MCI→MIA
Kansas City to Miami
- Flights
- 801
- Period
- July 2025 to June 2026
- Distance
- 1,251 mi
- Carriers
- 4
This route lands a B, 6 points better than the national rate of 77.6%. About one flight in six 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 801 MCI to MIA flights, with a median arrival 9 minutes early.
Best time to fly MCI to MIA: a 5am–8am departure, ideally on a Wednesday. Flights in that window arrived on time 88.9% of the time and Wednesday flights 87.6%, against 83.2% for the route overall.
Set against the rest of the country, this route's record is 6 points better than the US average of 77.6%. That gap is worth roughly 56 fewer late arrivals for every thousand flights.
Key figures
On time
83.2%
Arrivals under 15 minutes late, of 787 completed flights
Avg delay
75 min
Across delayed arrivals only, not all flights
Cancelled
1.37%
National rate is 1.81%
Best carrier
American
88.9% on time across 460 flights
These figures cover 801 flights between July 2025 and June 2026. The median arrival is 9 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 MCI to MIA
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 |
|---|---|---|---|---|---|
| American Airlines | 460 | 88.9% | 122 min | 1.74% | A |
| Envoy Airthin sample | 155 | 83.0% | 45 min | 1.29% | B |
| Southwest Airlinesthin sample | 181 | 70.0% | 48 min | 0.55% | C+ |
| Republic Airwaysthin sample | 5 | 60.0% | 31 min | 0.00% | D+ |
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 42 points, against half a point between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am434 flights88.9%
- 8am–11am79 flights79.5%
- 11am–2pm159 flights79.1%
- 2pm–5pm34 flights47.1%
- 5pm–8pm95 flights80.9%
- 8pm–5am—
Scale runs 40% to 95%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 88.9% of the time, against 47.1% for the afternoon window. That is 42 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 434 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 24 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.
July is the worst month at 73.1% on time, 24 points below October, the best at 96.8%. 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. March was the busiest month here, with 112 flights.
Across the week, Wednesday is the strongest day at 87.6% on time and Sunday the weakest at 78.0%. 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 53% of the 9,867 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.
- 53%Carrier
- 28%Late-arriving aircraft
- 17%National Airspace System
- 3%Extreme weather
The largest share of delay minutes, 53%, 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 5,239 of the 9,867 delay minutes reported here. The split is drawn from 9,867 reported delay minutes.
Cancellations sit at 1.37% against a national 1.81%, which is ordinary. Diversions add another 0.37%.
Connections and stage length
What a delay here actually costs
Badly late arrivals are rare here: only 4.7% land an hour or more behind schedule, against 8.1% nationally. Connections built on this flight are about as safe as US domestic connections get, though a cancelled flight still ignores every layover you give it.
The 1,251 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 72.8% on time across 801 flights, 10 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 10 points of difference.
One caution: this is a thin sample. 801 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.
Work out the risk of missing a connection in MIA after this flight
What to do with this
Booking this route
Put together: treat all of this as provisional. 801 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 83.2% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 787 completed flights over 12 months sit behind that.
Common questions
MCI to MIA questions
How often is MCI to MIA delayed?
About one flight in six arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 16.8% of the 801 flights in this analysis, against 22.4% nationally. Delayed flights are late by a little over an hour on average.
How reliable is MCI to MIA compared with the rest of the country?
83.2% of flights arrive on time here against a national 77.6%, a difference of 6 points in its favour. That is worth a B on this site's grading scale.
What time of day has the fewest delays on MCI to MIA?
The 5am–8am departure window is the strongest at 88.9% on time. The 2pm–5pm window is the weakest at 47.1%, 42 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 MCI to MIA?
July is the weakest month at 73.1% on time, compared with 96.8% in October. Across the year that is 24 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
- MIA to MCI — the return legseparate record
- Kansas City International (MCI) delay statistics
- Miami International (MIA) delay statistics
- American Airlines on MCI to MIA88.9%
- Envoy Air on MCI to MIA83.0%
- Southwest Airlines on MCI to MIA70.0%
- MCI to DEN, a related route76.1%
- ATL to MIA, a related route71.0%
- MCI to ORD, a related route74.7%
- American Airlines on-time record88.9%
- Envoy Air on-time record83.0%
- Southwest Airlines on-time record70.0%
- The best time of day to fly, according to 7.04 million flight records
- Worst months to fly in the US, ranked by the data
Direction matters. MCI to MIA and MIA to MCI 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.