Flight number record

UA 1281

United Airlines · Denver to San Diego

Route: DEN → SAN
Departs: 15:55
Flights: 309
Period: July 2025 to June 2026

Historical statistics for July 2025 to June 2026, not live status. For today’s UA 1281, check with United Airlines.

UA 1281 earns a B+. More than four flights in five arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 7 points better than the national rate of 77.6%. When something does go wrong the average delay runs about an hour. That rests on 309 flights, with a median arrival 6 minutes early.

Set against the rest of the country, UA 1281's record is 7 points better than the US average of 77.6%. That gap is worth roughly 70 fewer late arrivals for every thousand flights.

On time

84.6%

Arrivals under 15 minutes late, of 306 completed flights

Avg delay

68 min

Across delayed arrivals only, not all flights

Cancelled

0.65%

National rate is 1.81%

1 hour+ late

6.2%

National rate is 8.1%

These figures cover 309 flights between July 2025 and June 2026. The median arrival is 6 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.

Schedule

When UA 1281 flies

UA 1281 flies DEN to SAN without a single fixed slot. Its most common scheduled departure was 15:55, used on 94 of 309 flights, with 16:08 (78 flights) and 16:05 (38 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.

Departs 15:5594 flights30.4%
Departs 16:0878 flights25.2%
Departs 16:0538 flights12.3%

Scale runs 0% to 100%. Rows with fewer than 30 flights show a dash.

Share of scheduled departures at each local time. Times used on fewer than one flight in ten are not listed.

A 15:55 departure sits in the 2pm–5pm window. Across every US flight scheduled in that window the on-time rate is 72.4%, and UA 1281 runs 12 points better at 84.6%. Midday slots inherit some of the morning's delays without yet carrying the full weight of the evening's.

Against the route

UA 1281 next to DEN to SAN

Every carrier on DEN to SAN combined arrived on time 75.6% of the time across 5,949 flights, so UA 1281 is 9 points ahead of it. United flew 2,081 flights on the same city pair under all its flight numbers, including this one, and those ran 79.8% on time. Across its whole network United Airlines managed 79.0%, which this flight beats by 6 points.

UA 1281 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
UA 1281thin sample	309	84.6%	68 min	0.65%	B+
All United Airlines on DEN–SAN	2,081	79.8%	59 min	0.48%	B+
All carriers on DEN–SAN	5,949	75.6%	56 min	0.66%	B+
United Airlines, whole network	821,041	79.0%	72 min	1.01%	B

Across the year

UA 1281 quarter by quarter

UA 1281 did not run the same all year. Its best quarter was Oct–Dec 2025 at 92.7% on time and its weakest Jul–Sep 2025 at 70.3%, a swing of 22 points on roughly 77 flights a quarter. The twelve-month rate averages over that, so if you are flying in a weak quarter the quarter's own figure is the better guide.

Jul–Sep 202592 flights70.3%
Oct–Dec 202541 flights92.7%
Jan–Mar 202685 flights90.4%
Apr–Jun 202691 flights90.1%

Scale runs 60% to 100%. Rows with fewer than 30 flights show a dash.

By weekday, UA 1281 ranged from 80.4% on Tuesday to 90.9% on Saturday. With about 44 flights behind each day, a spread of 11 points is inside normal variation, so the day you fly is not worth changing for this flight.

Delay causes

Why UA 1281 runs late

One category carries most of the weight here. Late-arriving aircraft accounts for 44% of the 3,184 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
44%
Carrier
37%
National Airspace System
12%
Extreme weather
7%

44% 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 3,184 reported delay minutes here, that single category outweighs weather by 6 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 3,184 delay minutes reported on UA 1281.

Cancellations are rare at 0.65%, 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 routes

What a delay on this flight costs

6.2% 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 about an hour, which a normal layover absorbs.

The 853 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 same number turns up on five other city pairs in the data, including RAP to DEN (49), EWR to CLE (37) and ORD to MSP (21), but none flew often enough under UA 1281 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to DEN to SAN only.

One caution: this is a thin sample. 309 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 UA 1281

For a booking, read UA 1281 as 84.6% on time with 0.65% cancelled over 309 flights. Those are rates from the past twelve months, not a forecast for any particular day.

Where to go next

A flight number here means United Airlines’s own number as it reports to the DOT. How the figures are computed is on the methodology page.

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