Flight number record
UA 2177
United Airlines · San Francisco to San Diego
- Route
- SFO → SAN
- Departs
- 10:05
- Flights
- 310
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s UA 2177, check with United Airlines.
UA 2177 draws a D+. About one flight in three 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 310 flights, with a median arrival 4 minutes late.
The national on-time rate over the same period is 77.3%, so UA 2177 runs 13 points behind the country as a whole. Across a thousand flights that is about 125 extra late arrivals.
Key figures
On time
64.8%
Arrivals under 15 minutes late, of 310 completed flights
Avg delay
51 min
Across delayed arrivals only, not all flights
Cancelled
0.00%
National rate is 1.89%
1 hour+ late
8.1%
National rate is 8.3%
These figures cover 310 flights between September 2025 and August 2026. Beyond the headline rate, 8.1% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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Schedule
When UA 2177 flies
UA 2177 flies SFO to SAN without a single fixed slot. Its most common scheduled departure was 10:05, used on 82 of 310 flights, with 10:14 (49 flights) and 11:05 (38 flights) next.
- Departs 10:0582 flights26.5%
- Departs 10:1449 flights15.8%
- Departs 11:0538 flights12.3%
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 10:05 departure sits in the 8am–11am window. Across every US flight scheduled in that window the on-time rate is 83.9%, and UA 2177 runs 19 points worse at 64.8%. 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 2177 next to SFO to SAN
Every carrier on SFO to SAN combined arrived on time 62.2% of the time across 6,723 flights, so UA 2177 is 3 points ahead of it. United flew 2,666 flights on the same city pair under all its flight numbers, including this one, and those ran 72.8% on time. Across its whole network United Airlines managed 78.8%, which this flight trails by 14 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| UA 2177thin sample | 310 | 64.8% | 51 min | 0.00% | D+ |
| All United Airlines on SFO–SAN | 2,666 | 72.8% | 54 min | 0.34% | C+ |
| All carriers on SFO–SAN | 6,723 | 62.2% | 60 min | 1.25% | D |
| United Airlines, whole network | 830,825 | 78.8% | 73 min | 1.02% | B |
Across the year
UA 2177 quarter by quarter
UA 2177 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 48.4%, a swing of 34 points on roughly 78 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 202567 flights49.3%
- Jan–Mar 202690 flights82.2%
- Apr–Jun 202691 flights70.3%
- Jul–Sep 202662 flights48.4%
Scale runs 40% to 90%.
By weekday, UA 2177 did best on Saturday at 77.3% on time and worst on Thursday at 54.5%. Each day rests on about 44 flights, so a gap of 23 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late UA 2177 runs when it is late
The 109 late arrivals split 41 under half an hour, 43 between 30 and 60 minutes, and 25 an hour or more.
- 15+ min early33 flights10.6%
- Within 15 min168 flights54.2%
- 15–29 min late41 flights13.2%
- 30–59 min late43 flights13.9%
- 1–2 hours late18 flights5.8%
- 2+ hours late7 flights2.3%
Scale runs 0% to 100%.
Share of 310 completed flights by arrival against schedule.
Time lost at the gate mostly stays lost. Of 85 departures that left 15 minutes late or more, only 8 made it up before arrival. In the other direction, 32 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 SAN.
The worst days
Worst days for UA 2177
The latest arrival of the period was on 24 November 2025, 3 hours 34 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). On three of the five worst days the largest share was filed as a late-arriving aircraft.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 24 November 2025 | 3 hours 34 minutes | Carrier |
| 1 January 2026 | 3 hours 13 minutes | National Airspace System |
| 8 August 2026 | 3 hours 11 minutes | Late-arriving aircraft |
| 8 November 2025 | 3 hours 2 minutes | Late-arriving aircraft |
| 22 December 2025 | 2 hours 59 minutes | Late-arriving aircraft |
Delay causes
Why UA 2177 runs late
National Airspace System accounts for 47% of the 5,552 delay minutes carriers reported here, and the remaining four split what is left.
- 47%National Airspace System
- 34%Late-arriving aircraft
- 19%Carrier
34% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 5,552 reported delay minutes here, that single category outweighs weather by 34 to one. The split is drawn from 5,552 delay minutes reported on UA 2177.
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
8.1% 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 2177 is not only a SFO to SAN flight. It also flew AUS to SFO (270 flights, 92.5% 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. 310 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 |
|---|---|---|---|---|---|
| AUS to SFOthin sample | 270 | 92.5% | 76 min | 0.74% | A+ |
What to do with this
Booking UA 2177
For a booking, read UA 2177 as 64.8% on time with 0.00% cancelled over 310 flights. Those are rates from the past twelve months, not a forecast for any particular day.
Related
Where to go next
- SFO to SAN, every carrier and departure
- SAN to SFO, the return direction
- San Francisco International (SFO) delay statistics
- San Diego International (SAN) 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.