Carrier route record
UASMF→SFO
United Airlines · Sacramento to San Francisco
- Flights
- 115
- Period
- September 2025 to August 2026
- Share of route
- 8%
- Carriers
- 2
Historical statistics for September 2025 to August 2026, not live status. For today’s flights, check with United Airlines.
United on SMF to SFO earns an A+. Nearly every flight arrives inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 16 points better than the national rate of 77.3%. When something does go wrong the average delay runs about an hour. That rests on 115 flights, with a median arrival 8 minutes early.
Set against the rest of the country, United's SMF to SFO record is 16 points better than the US average of 77.3%. That gap is worth roughly 157 fewer late arrivals for every thousand flights.
Key figures
On time
93.0%
Arrivals under 15 minutes late, of 115 completed flights
Avg delay
65 min
Across delayed arrivals only, not all flights
Cancelled
0.00%
National rate is 1.89%
Whole route
62.2%
Every carrier on SMF to SFO, 1,360 flights
These figures cover 115 flights between September 2025 and August 2026. The median arrival is 8 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.
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Carrier by carrier
United against every carrier on SMF to SFO
United flew 115 of the 1,360 flights on SMF to SFO, about 8% of it. Its 93.0% on time is 31 points better than the route as a whole, which runs 62.2%. Ranked by on-time rate it is first of two carriers on the route, where the range runs from United at 93.0% to SkyWest at 59.3%.
Only one carrier clears this site's 365-flight floor here, so there is no comparison to draw. The table below is the full picture.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| United Airlines (this page)thin sample | 115 | 93.0% | 65 min | 0.00% | A+ |
| SkyWest Airlines | 1,245 | 59.3% | 72 min | 1.85% | D |
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Departure window
When United runs best on this route
Departure time is the single lever a traveller controls, and it moves the odds more than most people expect. Each bar below is the on-time rate for flights scheduled to leave inside that window, across 115 flights.
There are not enough flights in each departure window to split United's SMF to SFO record by time of day without the percentages moving on noise. The headline rate of 93.0% is the reliable figure here.
Across the year
United on SMF to SFO through the year
- Oct–Dec 20253 flights—
- Jan–Mar 202610 flights—
- Apr–Jun 202640 flights92.5%
- Jul–Sep 202662 flights93.5%
Scale runs 85% to 100%. Rows with fewer than 30 flights show a dash.
Monthly volumes are too low here to break the year into twelve reliable readings. What the twelve-month total says is 93.0% on time across 115 flights.
Split by quarter, United on SMF to SFO logged 3 flights in Oct–Dec 2025, 10 flights in Jan–Mar 2026, 40 flights in Apr–Jun 2026 and 62 flights in Jul–Sep 2026. Fewer than three of those quarters carried the 30 completed flights this site needs before printing a rate, so the 93.0% annual figure is the one to use.
Arrival by arrival
How late United on SMF to SFO runs when it is late
The 8 late arrivals split 3 under half an hour, 2 between 30 and 60 minutes, and 3 an hour or more.
- 15+ min early27 flights23.5%
- Within 15 min80 flights69.6%
- 15–29 min late3 flights2.6%
- 30–59 min late2 flights1.7%
- 1–2 hours late1 flights0.9%
- 2+ hours late2 flights1.7%
Scale runs 0% to 100%.
Share of 115 completed flights by arrival against schedule.
Only 5 of 115 completed flights left 15 minutes late or more, too few to say how often the time is made up.
The worst days
Worst days for United on SMF to SFO
The latest arrival of the period was on 22 July 2026, 2 hours 48 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). The same cause led on four of the five worst days.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 22 July 2026 | 2 hours 48 minutes | Carrier |
| 27 June 2026 | 2 hours 13 minutes | Carrier |
| 24 July 2026 | 1 hour 6 minutes | Carrier |
| 7 August 2026 | 52 minutes | Carrier |
| 1 June 2026 | 38 minutes | National Airspace System |
Delay causes
Why United runs late on this route
Carrier accounts for 66% of the 522 delay minutes carriers reported here, and the remaining four split what is left.
- 66%Carrier
- 34%National Airspace System
The largest share of delay minutes, 66%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 345 of the 522 delay minutes reported here. The split is drawn from 522 reported delay minutes.
34% 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 177 minutes out of 522, against a national NAS share of 21%.
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 stage length
What a delay here costs
Badly late arrivals are rare here: only 2.6% land an hour or more behind schedule, against 8.3% nationally. Connections built on this flight are about as safe as US domestic connections get, though a cancelled flight still ignores every layover you give it.
At 86 miles this is a short hop, and stage length matters more than it looks. A flight this short spends under two hours in the air, which leaves almost nothing to claw back a late pushback with. Delay here is decided on the ground, in the turn, which is why the 5am–8am window matters as much as it does.
The return leg is a different operation and performs like one: it runs 66.4% on time across 116 flights, 27 points below this direction. Departure banks, aircraft rotations and the congestion at each end all differ, so scoring the two directions together would average away a real 27 points of difference.
One caution: this is a thin sample. 115 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 United on SMF to SFO
Put together: treat all of this as provisional. 115 flights over twelve months is enough to clear this site's floor and not enough to be confident to better than a couple of points. The 93.0% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 115 completed flights over 12 months sit behind that.
Related
Where to go next
- SMF to SFO, every carrier
- United on SFO to SMF, the return leg
- SkyWest Airlines on SMF to SFO59.3%
- United Airlines network-wide record
- Sacramento International (SMF) delay statistics
- San Francisco International (SFO) delay statistics
- Late aircraft, weather, or the airline: what actually causes US flight delays
- How to read this site: grades, sample sizes, and honest caveats
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.