Route reliability record
DEN→MEM
Denver to Memphis
- Flights
- 1,395
- Period
- September 2025 to August 2026
- Distance
- 872 mi
- Carriers
- 4
This route lands a B+, about a point worse than 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 1,395 DEN to MEM flights, of which United Airlines flew 727 at 82.9% on time.
Best time to fly DEN to MEM: a 11am–2pm departure, ideally on a Thursday. Flights in that window arrived on time 85.2% of the time and Thursday flights 79.7%, against 76.4% 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
76.4%
Arrivals under 15 minutes late, of 1,381 completed flights
Avg delay
65 min
Across delayed arrivals only, not all flights
Cancelled
0.93%
National rate is 1.89%
Best carrier
United
82.9% on time across 727 flights
These figures cover 1,395 flights between September 2025 and August 2026. Beyond the headline rate, 8.4% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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Carrier by carrier
Which airline is most reliable on DEN to MEM
The choice of carrier is not cosmetic here. United Airlines arrives on time 82.9% of the time; Southwest Airlines manages 64.9%. Sample sizes sit next to every figure, because a two-point gap across 522 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| SkyWest Airlinesthin sample | 1 | 100.0% | — | 0.00% | A+ |
| Frontier Airlinesthin sample | 145 | 84.7% | 57 min | 0.69% | B+ |
| United Airlines | 727 | 82.9% | 73 min | 0.83% | B+ |
| Southwest Airlines | 522 | 64.9% | 60 min | 1.15% | D |
The spread between United and Southwest is 18 points, wide enough that it should decide the booking. On a hundred trips that is 18 more arrivals inside the on-time window.
Flight by flight
Flights on DEN to MEM
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 Memphis
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 → MEMDenver to Memphis | United Airlines | 82.2% | 82.9% | 0.83% | 11am–2pm, Tue | UA 2130 17:25 |
| 2. DEN → MEMDenver to Memphis | Southwest Airlines | 64.2% | 64.9% | 1.15% | 2pm–5pm, Tue | — |
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 32 points, against 18 points between the best and worst carrier.
- 5am–8am1 flights—
- 8am–11am143 flights82.5%
- 11am–2pm465 flights85.2%
- 2pm–5pm186 flights84.9%
- 5pm–8pm553 flights66.4%
- 8pm–5am47 flights53.2%
Scale runs 45% to 90%. Rows with fewer than 30 flights show a dash.
The 8pm–5am window is where this operation falls apart: 53.2% on time, against 85.2% for the 11am–2pm 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 553 flights scheduled in it.
Explore
Filter DEN to MEM 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 MEM, the best departure window is 11am–2pm at 85.2% on time and the worst is 8pm–5am at 53.2%, a wide gap of 32.0 points. All US flights leaving 11am–2pm ran 78.3%.
- 5–8am—
- 8–11am82.5%
- 11am–2pm85.2%
- 2–5pm84.9%
- 5–8pm66.4%
- 8pm–5am53.2%
best all US flightsScale 45% to 95%. Cells under 30 flights show a dash.
Across the year
When delays peak on this route
This route's year swings by 33 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.
June is the worst month at 60.9% on time, 33 points below November, the best at 94.1%. 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. August was the busiest month here, with 134 flights.
Across the week, Thursday is the strongest day at 79.7% on time and Friday the weakest at 69.7%, a spread of 10 points.
Delay causes
Why this route gets delayed
Late-arriving aircraft accounts for 57% of the 21,000 delay minutes carriers reported here, and the remaining four split what is left.
- 57%Late-arriving aircraft
- 31%Carrier
- 10%National Airspace System
- 2%Extreme weather
57% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 21,000 reported delay minutes here, that single category outweighs weather by 35 to one. The split is drawn from 21,024 reported delay minutes.
Cancellations sit at 0.93% against a national 1.89%, which is ordinary. Diversions add another 0.07%.
Connections and stage length
What a delay here actually costs
8.4% 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 872 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 77.7% on time across 1,395 flights, within about a point 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 1,395 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 MEM 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. November runs 94.1% on time and June 60.9%, a swing of 33 points. If the dates move at all, move them out of June before you think about anything else. 1,381 completed flights over 12 months sit behind that.
Common questions
DEN to MEM questions
How often is DEN to MEM 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 23.6% of the 1,395 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 MEM?
United Airlines leads at 82.9% on time across 727 flights. Southwest Airlines is at the other end on 64.9%, a gap of 18 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 MEM?
The 11am–2pm departure window is the strongest at 85.2% on time. The 8pm–5am window is the weakest at 53.2%, 32 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 June delays on DEN to MEM?
June is the weakest month at 60.9% on time, compared with 94.1% in November. Across the year that is 33 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
- MEM to DEN — the return legseparate record
- Denver International (DEN) delay statistics
- Memphis International (MEM) delay statistics
- Frontier Airlines on DEN to MEM84.7%
- United Airlines on DEN to MEM82.9%
- Southwest Airlines on DEN to MEM64.9%
- DEN to PHX, a related route75.6%
- ATL to MEM, a related route81.1%
- DEN to SLC, a related route78.2%
- SkyWest Airlines on-time record100.0%
- Frontier Airlines on-time record84.7%
- United Airlines on-time record82.9%
- 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 MEM and MEM 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.