Flight number record
UA 2356
United Airlines · Las Vegas to San Francisco
- Route
- LAS → SFO
- Departs
- 07:45
- Flights
- 346
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s UA 2356, check with United Airlines.
UA 2356 draws a D+. Roughly one flight in two arrives at least 15 minutes late, and the typical late arrival is about 50 minutes behind schedule. Build slack into anything you connect to. That rests on 346 flights, with a median arrival 6 minutes late.
The national on-time rate over the same period is 77.3%, so UA 2356 runs 18 points behind the country as a whole. Across a thousand flights that is about 182 extra late arrivals.
Key figures
On time
59.1%
Arrivals under 15 minutes late, of 345 completed flights
Avg delay
51 min
Across delayed arrivals only, not all flights
Cancelled
0.29%
National rate is 1.89%
1 hour+ late
7.0%
National rate is 8.3%
These figures cover 346 flights between September 2025 and August 2026. On-time means an arrival less than 15 minutes after the scheduled gate time, the same threshold the Department of Transportation uses in its own reports. Cancelled and diverted flights are excluded from the on-time rate and counted separately, which is why the cancellation column matters on its own.
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Schedule
When UA 2356 flies
UA 2356 flies LAS to SFO without a single fixed slot. Its most common scheduled departure was 07:45, used on 104 of 346 flights, with 07:15 (94 flights) and 07:30 (74 flights) next.
- Departs 07:45104 flights30.1%
- Departs 07:1594 flights27.2%
- Departs 07:3074 flights21.4%
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 07:45 departure sits in the 5am–8am window. Across every US flight scheduled in that window the on-time rate is 89.3%, and UA 2356 runs 30 points worse at 59.1%. Early departures usually start with an aircraft that has not flown yet that day, which is most of why the window does well.
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Against the route
UA 2356 next to LAS to SFO
Every carrier on LAS to SFO combined arrived on time 58.0% of the time across 6,137 flights, so UA 2356 is about level with it. United flew 2,816 flights on the same city pair under all its flight numbers, including this one, and those ran 62.6% on time. Across its whole network United Airlines managed 78.8%, which this flight trails by 20 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| UA 2356thin sample | 346 | 59.1% | 51 min | 0.29% | D+ |
| All United Airlines on LAS–SFO | 2,816 | 62.6% | 64 min | 0.43% | D+ |
| All carriers on LAS–SFO | 6,137 | 58.0% | 60 min | 0.77% | D+ |
| United Airlines, whole network | 830,825 | 78.8% | 73 min | 1.02% | B |
Across the year
UA 2356 quarter by quarter
UA 2356 did not run the same all year. Its best quarter was Jan–Mar 2026 at 80.0% on time and its weakest Jul–Sep 2026 at 40.7%, a swing of 39 points on roughly 69 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 flights53.3%
- Oct–Dec 202576 flights55.3%
- Jan–Mar 202690 flights80.0%
- Apr–Jun 202691 flights55.6%
- Jul–Sep 202659 flights40.7%
Scale runs 30% to 85%.
By weekday, UA 2356 did best on Saturday at 72.0% on time and worst on Wednesday at 42.9%. Each day rests on about 49 flights, so a gap of 29 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late UA 2356 runs when it is late
The 141 late arrivals split 56 under half an hour, 61 between 30 and 60 minutes, and 24 an hour or more.
- 15+ min early75 flights21.7%
- Within 15 min129 flights37.4%
- 15–29 min late56 flights16.2%
- 30–59 min late61 flights17.7%
- 1–2 hours late20 flights5.8%
- 2+ hours late4 flights1.2%
Scale runs 0% to 100%.
Share of 345 completed flights by arrival against schedule.
Time lost at the gate mostly stays lost. Of 65 departures that left 15 minutes late or more, only 2 made it up before arrival. In the other direction, 78 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 2356
The latest arrival of the period was on 8 August 2026, 17 hours 13 minutes behind schedule; most of its delay minutes were filed as a late-arriving aircraft. The five worst days are spread across August, June, May, April and January, with no single month standing out.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 8 August 2026 | 17 hours 13 minutes | Late-arriving aircraft |
| 5 June 2026 | 7 hours 23 minutes | Carrier |
| 28 May 2026 | 4 hours 43 minutes | National Airspace System |
| 30 April 2026 | 2 hours 37 minutes | National Airspace System |
| 5 January 2026 | 1 hour 48 minutes | Late-arriving aircraft |
Delay causes
Why UA 2356 runs late
National Airspace System accounts for 74% of the 7,123 delay minutes carriers reported here, and the remaining four split what is left.
- 74%National Airspace System
- 13%Late-arriving aircraft
- 12%Carrier
- 1%Extreme weather
74% 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 5,279 minutes out of 7,123, against a national NAS share of 21%. The split is drawn from 7,123 delay minutes reported on UA 2356.
Cancellations are rare at 0.29%, below the national 1.89% 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
7.0% of arrivals land an hour or more late, close to the national 8.3%, so a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last about 50 minutes, which a normal layover absorbs.
UA 2356 is not only a LAS to SFO flight. It also flew SFO to BOS (328 flights, 63.0% on time) often enough to be scored on its own. Airlines attach one number to several legs of an aircraft's day, and each leg keeps its own record here, so check which city pair is on your booking before reading a rate.
One caution: this is a thin sample. 346 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.
| Also flown as | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| SFO to BOSthin sample | 328 | 63.0% | 83 min | 0.91% | D+ |
What to do with this
Booking UA 2356
For a booking, read UA 2356 as 59.1% on time with 0.29% cancelled over 346 flights. Those are rates from the past twelve months, not a forecast for any particular day.
Related
Where to go next
- LAS to SFO, every carrier and departure
- SFO to LAS, the return direction
- United Airlines 574 on the same route66.1%
- Frontier Airlines 4401 on the same route48.0%
- United Airlines 2047 on the same route67.7%
- United Airlines 1799 on the same route52.8%
- Frontier Airlines 3801 on the same route60.1%
- Alaska Airlines 634 on the same route53.9%
- Harry Reid International (LAS) 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
- Worst months to fly in the US, ranked by the data
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.