Carrier route record

UASMF→DEN

United Airlines · Sacramento to Denver

Flights: 1,797
Period: July 2025 to June 2026
Share of route: 47%
Carriers: 3

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

United on SMF to DEN 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 11 points better than the national rate of 77.6%. When something does go wrong the average delay runs about an hour. That rests on 1,797 flights, with a median arrival 10 minutes early.

Set against the rest of the country, United's SMF to DEN record is 11 points better than the US average of 77.6%. That gap is worth roughly 107 fewer late arrivals for every thousand flights.

On time

88.3%

Arrivals under 15 minutes late, of 1,782 completed flights

Avg delay

64 min

Across delayed arrivals only, not all flights

Cancelled

0.50%

National rate is 1.81%

Whole route

82.5%

Every carrier on SMF to DEN, 3,834 flights

These figures cover 1,797 flights between July 2025 and June 2026. The median arrival is 10 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 SMF to DEN

United flew 1,797 of the 3,834 flights on SMF to DEN, about 47% of it. Its 88.3% on time is 6 points better than the route as a whole, which runs 82.5%. Ranked by on-time rate it is first of three carriers on the route, where the range runs from United at 88.3% to Southwest at 76.8%. One 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 SMF to DEN
Airline	Flights	On time	Avg delay	Cancelled	Grade
United Airlines (this page)	1,797	88.3%	64 min	0.50%	A+
Frontier Airlinesthin sample	173	81.9%	72 min	0.58%	B+
Southwest Airlines	1,864	76.8%	49 min	0.32%	B+

Flight by flight

United flight numbers on SMF to DEN

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 20 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–8am363 flights97.5%
8am–11am406 flights96.5%
11am–2pm468 flights85.1%
2pm–5pm334 flights80.5%
5pm–8pm224 flights77.8%
8pm–5am2 flights—

Scale runs 70% to 100%. Rows with fewer than 30 flights show a dash.

Book the early departure. Flights leaving between 5am–8am arrive on time 97.5% of the time, against 77.8% for the evening window. That is 20 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 11am–2pm window is the busiest, with 468 flights scheduled in it.

Across the year

United on SMF to DEN through the year

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

July is the worst month at 76.3% on time, 19 points below October, the best at 95.3%. 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. July was the busiest month here, with 180 flights.

Across the week, Saturday is the strongest day at 92.7% on time and Friday the weakest at 85.4%. 7 points is a smaller lever than departure hour, but it is free.

Delay causes

Why United runs late on this route

One category carries most of the weight here. Late-arriving aircraft accounts for 50% of the 13,000 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.

Late-arriving aircraft
50%
National Airspace System
29%
Carrier
19%
Extreme weather
2%

50% 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 13,000 reported delay minutes here, that single category outweighs weather by 27 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 13,323 reported delay minutes.

The practical consequence: the 5am–8am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 97.5% on time here.

Cancellations are rare at 0.50%, 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 costs

Badly late arrivals are rare here: only 4.3% 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 909 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 80.6% on time across 1,797 flights, 8 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 8 points of difference.

The sample behind these figures is 1,797 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.

What to do with this

Booking United on SMF to DEN

Put together: the calendar is the biggest lever here, not the carrier or the hour. October runs 95.3% on time and July 76.3%, a swing of 19 points. If the dates move at all, move them out of July before you think about anything else. 1,782 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