Flight number record
UA 2633
United Airlines · Denver to San Francisco
- Route
- DEN → SFO
- Departs
- 15:47
- Flights
- 364
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s UA 2633, check with United Airlines.
UA 2633 sits in the middle of the pack with a C+. About seven flights in ten arrive on time by the DOT's definition, 9 points worse than the national rate of 77.3%. The late ones land a little over an hour behind schedule. That rests on 364 flights, with a median arrival right on schedule.
The national on-time rate over the same period is 77.3%, so UA 2633 runs 9 points behind the country as a whole. Across a thousand flights that is about 86 extra late arrivals.
Key figures
On time
68.7%
Arrivals under 15 minutes late, of 364 completed flights
Avg delay
77 min
Across delayed arrivals only, not all flights
Cancelled
0.00%
National rate is 1.89%
1 hour+ late
13.7%
National rate is 8.3%
These figures cover 364 flights between September 2025 and August 2026. Beyond the headline rate, 13.7% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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Schedule
When UA 2633 flies
UA 2633 flies DEN to SFO without a single fixed slot. Its most common scheduled departure was 15:47, used on 82 of 364 flights, with 15:55 (63 flights) and 15:59 (52 flights) next.
- Departs 15:4782 flights22.5%
- Departs 15:5563 flights17.3%
- Departs 15:5952 flights14.3%
Scale runs 0% to 100%.
Share of scheduled departures at each local time. Times used on fewer than one flight in ten are not listed.
A 15:47 departure sits in the 2pm–5pm window. Across every US flight scheduled in that window the on-time rate is 71.9%, and UA 2633 runs 3 points worse at 68.7%. Midday slots inherit some of the morning's delays without yet carrying the full weight of the evening's.
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Against the route
UA 2633 next to DEN to SFO
Every carrier on DEN to SFO combined arrived on time 63.2% of the time across 5,488 flights, so UA 2633 is 6 points ahead of it. United flew 3,429 flights on the same city pair under all its flight numbers, including this one, and those ran 69.0% on time. Across its whole network United Airlines managed 78.8%, which this flight trails by 10 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| UA 2633thin sample | 364 | 68.7% | 77 min | 0.00% | C+ |
| All United Airlines on DEN–SFO | 3,429 | 69.0% | 63 min | 0.23% | C+ |
| All carriers on DEN–SFO | 5,488 | 63.2% | 62 min | 0.40% | D+ |
| United Airlines, whole network | 830,825 | 78.8% | 73 min | 1.02% | B |
Across the year
UA 2633 quarter by quarter
UA 2633 did not run the same all year. Its best quarter was Jan–Mar 2026 at 82.2% on time and its weakest Jul–Sep 2026 at 41.9%, a swing of 40 points on roughly 73 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 202530 flights76.7%
- Oct–Dec 202591 flights79.1%
- Jan–Mar 202690 flights82.2%
- Apr–Jun 202691 flights60.4%
- Jul–Sep 202662 flights41.9%
Scale runs 35% to 90%.
By weekday, UA 2633 ranged from 63.5% on Sunday to 73.1% on Tuesday. With about 52 flights behind each day, a spread of 10 points is inside normal variation, so the day you fly is not worth changing for this flight.
Arrival by arrival
How late UA 2633 runs when it is late
The 114 late arrivals split 39 under half an hour, 25 between 30 and 60 minutes, and 50 an hour or more.
- 15+ min early82 flights22.5%
- Within 15 min168 flights46.2%
- 15–29 min late39 flights10.7%
- 30–59 min late25 flights6.9%
- 1–2 hours late28 flights7.7%
- 2+ hours late22 flights6.0%
Scale runs 0% to 100%.
Share of 364 completed flights by arrival against schedule.
21 of 112 late departures made up the time and arrived on time, 19% of them. In the other direction, 23 flights left on time yet arrived 15 minutes late or more, so that delay built up after pushback: in the air, in a holding pattern or on the ground at SFO.
The worst days
Worst days for UA 2633
The latest arrival of the period was on 1 June 2026, 6 hours 24 minutes behind schedule; most of its delay minutes were filed as a late-arriving aircraft. The five worst days are spread across June, August, January and July, with no single month standing out.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 1 June 2026 | 6 hours 24 minutes | Late-arriving aircraft |
| 23 August 2026 | 5 hours 16 minutes | Late-arriving aircraft |
| 5 January 2026 | 5 hours 10 minutes | National Airspace System |
| 27 June 2026 | 5 hours 9 minutes | Carrier |
| 28 July 2026 | 5 hours 2 minutes | Carrier |
Delay causes
Why UA 2633 runs late
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 8,817 reported delay minutes.
- 40%Late-arriving aircraft
- 38%National Airspace System
- 21%Carrier
- 2%Extreme weather
40% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 8,817 reported delay minutes here, that single category outweighs weather by 25 to one. The split is drawn from 8,817 delay minutes reported on UA 2633.
Cancellations are rare at 0.00%, below the national 1.89% and low enough to earn the plus on the grade. Almost no flights are called off; the risk here is arriving late, not not arriving.
Connections and routes
What a delay on this flight costs
13.7% of arrivals land a full hour or more behind schedule, against 8.3% nationally. Ninety minutes is the honest minimum for a connection here, and two hours if the onward flight is on a separate ticket.
The 967 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 same number turns up on three other city pairs in the data, including SFO to SAN (64), CLE to DEN (26) and PHL to DEN (20), but none flew often enough under UA 2633 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to DEN to SFO only.
One caution: this is a thin sample. 364 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 2633
For a booking, UA 2633 is a flight to put a long connection behind. 13.7% of its completed flights arrived an hour or more late, which a short layover will not absorb. If the onward flight is on a separate ticket, the risk sits with you.
Related
Where to go next
- DEN to SFO, every carrier and departure
- SFO to DEN, the return direction
- United Airlines 1812 on the same route73.4%
- United Airlines 2391 on the same route71.7%
- United Airlines 2367 on the same route95.3%
- United Airlines 1007 on the same route66.2%
- United Airlines 1561 on the same route66.8%
- United Airlines 2123 on the same route56.6%
- Denver International (DEN) delay statistics
- San Francisco International (SFO) delay statistics
- United Airlines on-time record
- Every United Airlines flight number with a record
- The most and least reliable flight numbers in the US
- Why the first flight of the morning is statistically safest
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, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.