Carrier route record
UASLC→SFO
United Airlines · Salt Lake City to San Francisco
- Flights
- 484
- Period
- July 2025 to June 2026
- Share of route
- 14%
- Carriers
- 4
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with United Airlines.
United on SLC to SFO lands a B+, about a point worse than the national rate of 77.6%. About one flight in four arrives 15 minutes late or worse, and those flights are late by a little over an hour on average. That is a workable record, not a spotless one. That rests on 484 flights. The strongest carrier on the route with a full sample, SkyWest Airlines, flew 1,104 at 68.8% on time.
The US average over the same twelve months is 77.6%, so there is little to separate United on SLC to SFO from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
76.6%
Arrivals under 15 minutes late, of 483 completed flights
Avg delay
72 min
Across delayed arrivals only, not all flights
Cancelled
0.21%
National rate is 1.81%
Whole route
69.0%
Every carrier on SLC to SFO, 3,472 flights
These figures cover 484 flights between July 2025 and June 2026. Beyond the headline rate, 9.3% of arrivals land a full hour or more behind schedule. That is the number that wrecks a connection, and it is not visible in an on-time percentage alone.
Carrier by carrier
United against every carrier on SLC to SFO
United flew 484 of the 3,472 flights on SLC to SFO, about 14% of it. Its 76.6% on time is 8 points better than the route as a whole, which runs 69.0%. Ranked by on-time rate it is first of four carriers on the route, where the range runs from United at 76.6% to Frontier at 66.3%. One of those carriers flew fewer than 365 flights here, so treat their positions as rough.
The two carriers here are closely matched: about a point separate the best from the worst. At that spread, schedule and price are better tie-breakers than reliability. Sample sizes are shown so you can see which rows are worth weighing.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| United Airlines (this page) | 484 | 76.6% | 72 min | 0.21% | B+ |
| SkyWest Airlines | 1,104 | 68.8% | 76 min | 1.27% | C |
| Delta Air Lines | 1,706 | 67.4% | 52 min | 0.88% | C+ |
| Frontier Airlinesthin sample | 178 | 66.3% | 95 min | 1.69% | C |
No carrier stands out. SkyWest tops the table at 68.8%, about a point clear of the bottom, which is inside the range this kind of sample moves year to year.
Departure window
When United runs best on this route
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 44 points, against about a point between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am5 flights—
- 8am–11am57 flights73.7%
- 11am–2pm119 flights89.1%
- 2pm–5pm229 flights80.3%
- 5pm–8pm—
- 8pm–5am74 flights45.2%
Scale runs 35% to 95%. Rows with fewer than 30 flights show a dash.
The 8pm–5am window is where this operation falls apart: 45.2% on time, against 89.1% for the 11am–2pm slot. By evening the aircraft flying these rotations have absorbed a full day of small delays and there is no slack left to recover in. The 2pm–5pm window is the busiest, with 229 flights scheduled in it.
Across the year
United on SLC to SFO through the year
June is the worst month at 36.2% on time, 55 points below January, the best at 90.9%. Summer afternoon convection and peak-season schedules land on the same weeks every year, so this is a pattern you can book around rather than a run of bad luck. February was the busiest month here, with 76 flights.
Across the week, Tuesday is the strongest day at 80.6% on time and Wednesday the weakest at 70.0%. 11 points is a smaller lever than departure hour, but it is free.
Delay causes
Why United runs late on this route
One category carries most of the weight here. National Airspace System accounts for 53% of the 8,091 delay minutes carriers reported, and the remaining four split what is left. The split is by minutes rather than by flights, so a few very long delays count for as much as many short ones.
- 53%National Airspace System
- 33%Late-arriving aircraft
- 13%Carrier
- 0%Extreme weather
53% 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 4,303 minutes out of 8,091, against a national NAS share of 21%. The split is drawn from 8,091 reported delay minutes.
Cancellations are rare at 0.21%, below the national 1.81% 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 stage length
What a delay here costs
For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 9.3% of arrivals land a full hour or more behind schedule, against 8.1% nationally. A 45-minute layover does not survive that, and no amount of walking quickly changes it. Ninety minutes is the honest minimum here, and two hours if the onward flight is on a separate ticket.
The 599 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. It is also long enough that the aircraft usually flies three or four legs a day rather than six, which slows how fast delay compounds.
The return leg runs 76.7% on time across 482 flights, within half a point of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.
One caution: this is a thin sample. 484 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 SLC to SFO
Put together: treat all of this as provisional. 484 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 76.6% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 483 completed flights over 12 months sit behind that.
Related
Where to go next
- SLC to SFO, every carrier
- United on SFO to SLC, the return leg
- SkyWest Airlines on SLC to SFO68.8%
- Delta Air Lines on SLC to SFO67.4%
- Frontier Airlines on SLC to SFO66.3%
- United Airlines network-wide record
- Salt Lake City International (SLC) delay statistics
- San Francisco International (SFO) delay statistics
- Why the first flight of the morning is statistically safest
- How often a connection fails at the major US hubs
Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.