Flight number record
UA 1596
United Airlines · San Francisco to Denver
- Route
- SFO → DEN
- Departs
- 14:20
- Flights
- 257
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s UA 1596, check with United Airlines.
UA 1596 draws a C+. About one flight in three arrives at least 15 minutes late, and the typical late arrival is about an hour behind schedule. Build slack into anything you connect to. That rests on 257 flights, with a median arrival right on schedule.
The national on-time rate over the same period is 77.3%, so UA 1596 runs 10 points behind the country as a whole. Across a thousand flights that is about 96 extra late arrivals.
Key figures
On time
67.7%
Arrivals under 15 minutes late, of 254 completed flights
Avg delay
64 min
Across delayed arrivals only, not all flights
Cancelled
0.00%
National rate is 1.89%
1 hour+ late
12.2%
National rate is 8.3%
These figures cover 257 flights between September 2025 and August 2026. Beyond the headline rate, 12.2% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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Schedule
When UA 1596 flies
UA 1596 flies SFO to DEN without a single fixed slot. Its most common scheduled departure was 14:20, used on 103 of 257 flights, with 14:42 (37 flights) and 14:32 (32 flights) next.
- Departs 14:20103 flights40.1%
- Departs 14:4237 flights14.4%
- Departs 14:3232 flights12.5%
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 14:20 departure sits in the 2pm–5pm window. Across every US flight scheduled in that window the on-time rate is 71.9%, and UA 1596 runs 4 points worse at 67.7%. 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 1596 next to SFO to DEN
Every carrier on SFO to DEN combined arrived on time 74.7% of the time across 5,486 flights, so UA 1596 is 7 points behind it. United flew 3,427 flights on the same city pair under all its flight numbers, including this one, and those ran 82.1% on time. Across its whole network United Airlines managed 78.8%, which this flight trails by 11 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| UA 1596thin sample | 257 | 67.7% | 64 min | 0.00% | C+ |
| All United Airlines on SFO–DEN | 3,427 | 82.1% | 58 min | 0.18% | B+ |
| All carriers on SFO–DEN | 5,486 | 74.7% | 61 min | 0.46% | C+ |
| United Airlines, whole network | 830,825 | 78.8% | 73 min | 1.02% | B |
Across the year
UA 1596 quarter by quarter
UA 1596 did not run the same all year. Its best quarter was Jan–Mar 2026 at 78.9% on time and its weakest Jul–Sep 2026 at 55.0%, a swing of 24 points on roughly 86 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.
- Oct–Dec 202514 flights—
- Jan–Mar 202690 flights78.9%
- Apr–Jun 202691 flights67.8%
- Jul–Sep 202662 flights55.0%
Scale runs 45% to 85%. Rows with fewer than 30 flights show a dash.
By weekday, UA 1596 ranged from 63.9% on Friday to 75.7% on Saturday. With about 37 flights behind each day, a spread of 12 points is inside normal variation, so the day you fly is not worth changing for this flight.
Arrival by arrival
How late UA 1596 runs when it is late
The 82 late arrivals split 27 under half an hour, 24 between 30 and 60 minutes, and 31 an hour or more.
- 15+ min early45 flights17.7%
- Within 15 min127 flights50.0%
- 15–29 min late27 flights10.6%
- 30–59 min late24 flights9.4%
- 1–2 hours late20 flights7.9%
- 2+ hours late11 flights4.3%
Scale runs 0% to 100%.
Share of 254 completed flights by arrival against schedule.
14 of 82 late departures made up the time and arrived on time, 17% of them. In the other direction, 14 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 DEN.
The worst days
Worst days for UA 1596
The latest arrival of the period was on 18 July 2026, 5 hours 39 minutes behind schedule; most of its delay minutes were filed as a late-arriving aircraft. The five worst days are spread across July, August, December and June, with no single month standing out.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 18 July 2026 | 5 hours 39 minutes | Late-arriving aircraft |
| 14 August 2026 | 4 hours 6 minutes | National Airspace System |
| 19 December 2025 | 3 hours 9 minutes | Late-arriving aircraft |
| 8 June 2026 | 3 hours | National Airspace System |
| 16 August 2026 | 2 hours 29 minutes | Carrier |
Delay causes
Why UA 1596 runs late
National Airspace System accounts for 47% of the 5,240 delay minutes carriers reported here, and the remaining four split what is left.
- 47%National Airspace System
- 35%Late-arriving aircraft
- 18%Carrier
35% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 5,240 reported delay minutes here, that single category outweighs weather by 35 to one. The split is drawn from 5,240 delay minutes reported on UA 1596.
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
12.2% 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 seven other city pairs in the data, including DEN to MCI (148), PDX to SFO (82) and BWI to SFO (53), but none flew often enough under UA 1596 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to SFO to DEN only.
One caution: this is a thin sample. 257 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 1596
For a booking, UA 1596 is a flight to put a long connection behind. 12.2% 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
- SFO to DEN, every carrier and departure
- DEN to SFO, the return direction
- Frontier Airlines 1230 on the same route89.1%
- United Airlines 1430 on the same route76.4%
- United Airlines 2348 on the same route81.9%
- San Francisco International (SFO) delay statistics
- Denver International (DEN) 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.