Carrier route record
UASFO→SLC
United Airlines · San Francisco to Salt Lake City
- Flights
- 482
- 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 SFO to SLC 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 about 55 minutes on average. That is a workable record, not a spotless one. That rests on 482 flights. The strongest carrier on the route with a full sample, Delta Air Lines, flew 1,708 at 78.1% on time.
The US average over the same twelve months is 77.6%, so there is little to separate United on SFO to SLC from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
76.7%
Arrivals under 15 minutes late, of 481 completed flights
Avg delay
55 min
Across delayed arrivals only, not all flights
Cancelled
0.21%
National rate is 1.81%
Whole route
77.2%
Every carrier on SFO to SLC, 3,471 flights
These figures cover 482 flights between July 2025 and June 2026. The median arrival is 3 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.
Carrier by carrier
United against every carrier on SFO to SLC
United flew 482 of the 3,471 flights on SFO to SLC, about 14% of it. Its 76.7% on time is about level with the route as a whole at 77.2%. Ranked by on-time rate it is number three of four carriers on the route, where the range runs from Delta at 78.1% to Frontier at 69.9%. 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 |
|---|---|---|---|---|---|
| Delta Air Lines | 1,708 | 78.1% | 77 min | 0.88% | B+ |
| SkyWest Airlines | 1,103 | 77.2% | 63 min | 1.18% | B |
| United Airlines (this page) | 482 | 76.7% | 55 min | 0.21% | B+ |
| Frontier Airlinesthin sample | 178 | 69.9% | 82 min | 1.12% | C |
No carrier stands out. Delta tops the table at 78.1%, 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 24 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–8am—
- 8am–11am192 flights87.5%
- 11am–2pm69 flights75.4%
- 2pm–5pm175 flights63.8%
- 5pm–8pm46 flights82.6%
- 8pm–5am—
Scale runs 55% to 95%. Rows with fewer than 30 flights show a dash.
Book the morning departure. Flights leaving between 8am–11am arrive on time 87.5% of the time, against 63.8% for the afternoon window. That is 24 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 8am–11am window is the busiest, with 192 flights scheduled in it.
Across the year
United on SFO to SLC through the year
June is the worst month at 50.0% on time, 42 points below January, the best at 92.4%. 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, Saturday is the strongest day at 86.6% on time and Thursday the weakest at 69.9%. 17 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. Late-arriving aircraft accounts for 63% of the 6,122 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.
- 63%Late-arriving aircraft
- 27%Carrier
- 10%National Airspace System
63% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. That is a cascade, and cascades start small and grow through the day. Across 6,122 reported delay minutes here, that single category outweighs weather by 63 to one. It is the strongest argument for booking the first departure of the morning, when the aircraft has been sitting at the gate overnight with nothing to inherit. The split is drawn from 6,122 reported delay minutes.
The practical consequence: the 8am–11am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 87.5% on time here.
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
7.3% of arrivals land an hour or more late, close to the national 8.1%. That is the figure that decides a connection, and it says a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last about 55 minutes, which a normal layover absorbs.
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 76.6% on time across 484 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. 482 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 SLC
Put together: treat all of this as provisional. 482 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 76.7% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 481 completed flights over 12 months sit behind that.
Related
Where to go next
- SFO to SLC, every carrier
- United on SLC to SFO, the return leg
- Delta Air Lines on SFO to SLC78.1%
- SkyWest Airlines on SFO to SLC77.2%
- Frontier Airlines on SFO to SLC69.9%
- United Airlines network-wide record
- San Francisco International (SFO) delay statistics
- Salt Lake City International (SLC) delay statistics
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.04 million flight records
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.