Carrier route record

UAMEM→DEN

United Airlines · Memphis to Denver

Flights: 728
Period: July 2025 to June 2026
Share of route: 55%
Carriers: 4

Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with United Airlines.

United on MEM to DEN lands a B, 4 points 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 728 flights, with a median arrival 7 minutes early.

The US average over the same twelve months is 77.6%, so there is little to separate United on MEM to DEN from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.

On time

81.2%

Arrivals under 15 minutes late, of 718 completed flights

Avg delay

79 min

Across delayed arrivals only, not all flights

Cancelled

1.10%

National rate is 1.81%

Whole route

78.8%

Every carrier on MEM to DEN, 1,333 flights

These figures cover 728 flights between July 2025 and June 2026. The median arrival is 7 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

United against every carrier on MEM to DEN

United flew 728 of the 1,333 flights on MEM to DEN, most of the route. Its 81.2% on time is 2 points better than the route as a whole, which runs 78.8%. Ranked by on-time rate it is number two of four carriers on the route, where the range runs from SkyWest at 100.0% to Frontier at 74.6%. Two of those carriers flew fewer than 365 flights here, so treat their positions as rough.

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.

On-time performance by carrier on MEM to DEN
Airline	Flights	On time	Avg delay	Cancelled	Grade
SkyWest Airlinesthin sample	1	100.0%	—	0.00%	A+
United Airlines (this page)	728	81.2%	79 min	1.10%	B
Southwest Airlines	465	76.3%	56 min	0.65%	B+
Frontier Airlinesthin sample	139	74.6%	95 min	0.72%	C+

Departure window

When United runs best on this route

Departure time matters more here than the choice of carrier. The gap between the best and worst window is 13 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–8am—
8am–11am364 flights87.5%
11am–2pm—
2pm–5pm364 flights74.9%
5pm–8pm—
8pm–5am—

Scale runs 65% to 95%. Rows with fewer than 30 flights show a dash.

Book the morning departure. Flights leaving between 8am–11am arrive on time 87.5% of the time, against 74.9% for the afternoon window. That is 13 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 8am–11am window is the busiest, with 364 flights scheduled in it.

Across the year

United on MEM to DEN through the year

Darker means more delays. Figures are on-time percentages.November best, July worst

July is the worst month at 69.4% on time, 27 points below November, the best at 96.6%. 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. January was the busiest month here, with 62 flights.

The day of the week is close to irrelevant here: 3 points separates the best day from the worst. Weekly demand peaks are not what drives the delays on this operation.

Delay causes

Why United runs late on this route

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 11,000 reported delay minutes.

Carrier
39%
National Airspace System
36%
Late-arriving aircraft
22%
Extreme weather
4%

The largest share of delay minutes, 39%, 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 4,084 of the 11,000 delay minutes reported here. The split is drawn from 10,601 reported delay minutes.

36% 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 3,790 minutes out of 11,000, against a national NAS share of 21%.

Cancellations sit at 1.10% against a national 1.81%, which is ordinary. Diversions add another 0.27%.

Connections and stage length

What a delay here costs

7.0% 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 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. 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 runs 81.0% on time across 728 flights, within half a point 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. 728 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.

What to do with this

Booking United on MEM to DEN

Put together: treat all of this as provisional. 728 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 81.2% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 718 completed flights over 12 months sit behind that.

Where to go next

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.

Key figures