Carrier route record
UASFO→SMF
United Airlines · San Francisco to Sacramento
- Flights
- 116
- Period
- September 2025 to August 2026
- Share of route
- 9%
- Carriers
- 2
Historical statistics for September 2025 to August 2026, not live status. For today’s flights, check with United Airlines.
United on SFO to SMF draws a C+. 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 116 flights, with a median arrival 5 minutes late.
The national on-time rate over the same period is 77.3%, so United on SFO to SMF runs 11 points behind the country as a whole. Across a thousand flights that is about 109 extra late arrivals.
Key figures
On time
66.4%
Arrivals under 15 minutes late, of 116 completed flights
Avg delay
49 min
Across delayed arrivals only, not all flights
Cancelled
0.00%
National rate is 1.89%
Whole route
76.0%
Every carrier on SFO to SMF, 1,359 flights
These figures cover 116 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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Carrier by carrier
United against every carrier on SFO to SMF
United flew 116 of the 1,359 flights on SFO to SMF, about 9% of it. Its 66.4% on time is 10 points worse than the route as a whole, which runs 76.0%. Ranked by on-time rate it is last of two carriers on the route, where the range runs from SkyWest at 77.0% to United at 66.4%.
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 |
|---|---|---|---|---|---|
| SkyWest Airlines | 1,243 | 77.0% | 79 min | 1.77% | B |
| United Airlines (this page)thin sample | 116 | 66.4% | 49 min | 0.00% | C+ |
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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 116 flights.
There are not enough flights in each departure window to split United's SFO to SMF record by time of day without the percentages moving on noise. The headline rate of 66.4% is the reliable figure here.
Across the year
United on SFO to SMF through the year
- Oct–Dec 20252 flights—
- Jan–Mar 202611 flights—
- Apr–Jun 202641 flights61.0%
- Jul–Sep 202662 flights64.5%
Scale runs 55% to 70%. 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 66.4% on time across 116 flights.
Split by quarter, United on SFO to SMF logged 2 flights in Oct–Dec 2025, 11 flights in Jan–Mar 2026, 41 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 66.4% annual figure is the one to use.
Arrival by arrival
How late United on SFO to SMF runs when it is late
The 39 late arrivals split 13 under half an hour, 17 between 30 and 60 minutes, and 9 an hour or more.
- 15+ min early14 flights12.1%
- Within 15 min63 flights54.3%
- 15–29 min late13 flights11.2%
- 30–59 min late17 flights14.7%
- 1–2 hours late8 flights6.9%
- 2+ hours late1 flights0.9%
Scale runs 0% to 100%.
Share of 116 completed flights by arrival against schedule.
14 of 49 late departures made up the time and arrived on time, 29% of them. 4 flights left on time and still arrived late.
The worst days
Worst days for United on SFO to SMF
The latest arrival of the period was on 7 July 2026, 3 hours 51 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). On four of the five worst days the largest share was filed as a late-arriving aircraft.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 7 July 2026 | 3 hours 51 minutes | Carrier |
| 28 May 2026 | 1 hour 45 minutes | Late-arriving aircraft |
| 3 June 2026 | 1 hour 43 minutes | Late-arriving aircraft |
| 27 June 2026 | 1 hour 33 minutes | Late-arriving aircraft |
| 27 July 2026 | 1 hour 33 minutes | Late-arriving aircraft |
Delay causes
Why United runs late on this route
Late-arriving aircraft accounts for 64% of the 1,911 delay minutes carriers reported here, and the remaining four split what is left.
- 64%Late-arriving aircraft
- 30%Carrier
- 6%National Airspace System
64% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 1,911 reported delay minutes here, that single category outweighs weather by 64 to one. The split is drawn from 1,911 reported delay minutes.
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
7.8% 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.
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 8pm–5am window matters as much as it does.
The return leg is a different operation and performs like one: it runs 93.0% on time across 115 flights, 27 points above 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. 116 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 SFO to SMF
Put together: treat all of this as provisional. 116 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 66.4% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 116 completed flights over 12 months sit behind that.
Related
Where to go next
- SFO to SMF, every carrier
- United on SMF to SFO, the return leg
- SkyWest Airlines on SFO to SMF77.0%
- United Airlines network-wide record
- San Francisco International (SFO) delay statistics
- Sacramento International (SMF) delay statistics
- Why the first flight of the morning is statistically safest
- 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.