Route reliability record
MCI→SLC
Kansas City to Salt Lake City
- Flights
- 1,005
- Period
- September 2025 to August 2026
- Distance
- 920 mi
- Carriers
- 1
This route earns an A+. Close to nine flights in ten arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 10 points better than the national rate of 77.3%. When something does go wrong the average delay runs about an hour. That rests on 1,005 MCI to SLC flights, with a median arrival 11 minutes early.
Best time to fly MCI to SLC: a 5am–8am departure, ideally on a Wednesday. Flights in that window arrived on time 91.8% of the time and Wednesday flights 90.3%, against 87.0% for the route overall.
Set against the rest of the country, this route's record is 10 points better than the US average of 77.3%. That gap is worth roughly 97 fewer late arrivals for every thousand flights.
Key figures
On time
87.0%
Arrivals under 15 minutes late, of 992 completed flights
Avg delay
61 min
Across delayed arrivals only, not all flights
Cancelled
0.90%
National rate is 1.89%
Best carrier
Delta
87.0% on time across 1,005 flights
These figures cover 1,005 flights between September 2025 and August 2026. The median arrival is 11 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 MCI to SLC
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 |
|---|---|---|---|---|---|
| Delta Air Lines | 1,005 | 87.0% | 61 min | 0.90% | A+ |
Flight by flight
Flights on MCI to SLC
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.
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.
Departure window
The best time of day to leave
Departure time is the single lever a traveller controls, and it moves the odds more than most people expect. Each bar below is the on-time rate for flights scheduled to leave inside that window, across 1,005 flights.
- 5am–8am349 flights91.8%
- 8am–11am16 flights—
- 11am–2pm—
- 2pm–5pm362 flights85.0%
- 5pm–8pm212 flights83.8%
- 8pm–5am66 flights82.8%
Scale runs 75% to 95%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 91.8% of the time, against 82.8% for the overnight window. That is 9 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 362 flights scheduled in it.
Explore
Filter MCI to SLC 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 MCI to SLC, the best departure window is 5am–8am at 91.8% on time and the worst is 8pm–5am at 82.8%, a real gap of 9.0 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am91.8%
- 8–11am—
- 11am–2pm—
- 2–5pm85.0%
- 5–8pm83.8%
- 8pm–5am82.8%
best all US flightsScale 60% to 95%. Cells under 30 flights show a dash.
Across the year
When delays peak on this route
This route's year swings by 18 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 76.4% on time, against 94.1% in May. 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. October was the busiest month here, with 91 flights.
Across the week, Wednesday is the strongest day at 90.3% on time and Monday the weakest at 79.7%, a spread of 11 points.
Delay causes
Why this route gets delayed
Late-arriving aircraft accounts for 45% of the 7,926 delay minutes carriers reported here, and the remaining four split what is left.
- 45%Late-arriving aircraft
- 37%Carrier
- 16%National Airspace System
- 2%Extreme weather
45% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 7,926 reported delay minutes here, that single category outweighs weather by 25 to one. The split is drawn from 7,926 reported delay minutes.
The largest share of delay minutes, 37%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 2,969 of the 7,926 delay minutes reported here.
Cancellations sit at 0.90% against a national 1.89%, which is ordinary. Diversions add another 0.40%.
Connections and stage length
What a delay here actually costs
Badly late arrivals are rare here: only 4.1% land an hour or more behind schedule, against 8.3% 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 920 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 85.4% on time across 1,005 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.
One caution: this is a thin sample. 1,005 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 SLC after this flight
What to do with this
Booking this route
Put together: treat all of this as provisional. 1,005 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 87.0% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 992 completed flights over 12 months sit behind that.
Common questions
MCI to SLC questions
How often is MCI to SLC delayed?
About one flight in eight arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 13.0% of the 1,005 flights in this analysis, against 22.7% nationally. Delayed flights are late by about an hour on average.
How reliable is MCI to SLC compared with the rest of the country?
87.0% of flights arrive on time here against a national 77.3%, a difference of 10 points in its favour. That is worth a A+ on this site's grading scale.
What time of day has the fewest delays on MCI to SLC?
The 5am–8am departure window is the strongest at 91.8% on time. The 8pm–5am window is the weakest at 82.8%, 9 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 MCI to SLC?
December is the weakest month at 76.4% on time, compared with 94.1% in May. Across the year that is 18 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
- SLC to MCI — the return legseparate record
- Kansas City International (MCI) delay statistics
- Salt Lake City International (SLC) delay statistics
- MCI to DEN, a related route78.1%
- DEN to SLC, a related route78.2%
- MCI to ORD, a related route74.6%
- Delta Air Lines on-time record87.0%
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.05 million flight records
Direction matters. MCI to SLC and SLC 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, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.