Carrier route record
UASFO→SLC
United Airlines · San Francisco to Salt Lake City
- Flights
- 503
- Period
- September 2025 to August 2026
- Share of route
- 15%
- Carriers
- 4
Historical statistics for September 2025 to August 2026, not live status. For today’s flights, check with United Airlines.
United on SFO to SLC sits in the middle of the pack with a C+. Close to three flights in four arrive on time by the DOT's definition, 3 points worse than the national rate of 77.3%. The late ones land about an hour behind schedule. That rests on 503 flights. The strongest carrier on the route with a full sample, SkyWest Airlines, flew 1,008 at 75.9% on time.
The US average over the same twelve months is 77.3%, 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
74.7%
Arrivals under 15 minutes late, of 501 completed flights
Avg delay
57 min
Across delayed arrivals only, not all flights
Cancelled
0.20%
National rate is 1.89%
Whole route
75.0%
Every carrier on SFO to SLC, 3,431 flights
These figures cover 503 flights between September 2025 and August 2026. Beyond the headline rate, 8.4% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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Carrier by carrier
United against every carrier on SFO to SLC
United flew 503 of the 3,431 flights on SFO to SLC, about 15% of it. Its 74.7% on time is about level with the route as a whole at 75.0%. Ranked by on-time rate it is number three of four carriers on the route, where the range runs from SkyWest at 75.9% to Frontier at 65.8%. One of those carriers flew fewer than 365 flights here, so treat their positions as rough.
The two carriers here are closely matched: half 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 |
|---|---|---|---|---|---|
| SkyWest Airlines | 1,008 | 75.9% | 68 min | 1.39% | B |
| Delta Air Lines | 1,714 | 75.7% | 74 min | 0.93% | B+ |
| United Airlines (this page) | 503 | 74.7% | 57 min | 0.20% | C+ |
| Frontier Airlinesthin sample | 206 | 65.8% | 76 min | 1.94% | C |
No carrier stands out. SkyWest tops the table at 75.9%, half a point clear of the bottom, which is inside the range this kind of sample moves year to year.
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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 25 points, against half a point between the best and worst carrier.
- 5am–8am—
- 8am–11am184 flights87.5%
- 11am–2pm56 flights73.2%
- 2pm–5pm217 flights62.3%
- 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 62.3% for the afternoon window. That is 25 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 2pm–5pm window is the busiest, with 217 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 84.7% on time and Thursday the weakest at 64.9%, a spread of 20 points.
Arrival by arrival
How late United on SFO to SLC runs when it is late
The 127 late arrivals split 40 under half an hour, 45 between 30 and 60 minutes, and 42 an hour or more.
- 15+ min early84 flights16.8%
- Within 15 min290 flights57.9%
- 15–29 min late40 flights8.0%
- 30–59 min late45 flights9.0%
- 1–2 hours late32 flights6.4%
- 2+ hours late10 flights2.0%
Scale runs 0% to 100%.
Share of 501 completed flights by arrival against schedule.
22 of 129 late departures made up the time and arrived on time, 17% of them. 20 flights left on time and still arrived late.
The worst days
Worst days for United on SFO to SLC
The latest arrival of the period was on 28 February 2026, 4 hours 26 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 |
|---|---|---|
| 28 February 2026 | 4 hours 26 minutes | Carrier |
| 13 June 2026 | 3 hours 45 minutes | Late-arriving aircraft |
| 11 June 2026 | 3 hours 44 minutes | Carrier |
| 15 February 2026 | 3 hours 23 minutes | Late-arriving aircraft |
| 23 May 2026 | 3 hours 11 minutes | Late-arriving aircraft |
Delay causes
Why United runs late on this route
Late-arriving aircraft accounts for 63% of the 7,212 delay minutes carriers reported here, and the remaining four split what is left.
- 63%Late-arriving aircraft
- 26%Carrier
- 11%National Airspace System
63% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 7,212 reported delay minutes here, that single category outweighs weather by 63 to one. The split is drawn from 7,212 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 0.20%, below the national 1.89% 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
8.4% 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 an hour, 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.
The return leg is a different operation and performs like one: it runs 68.2% on time across 504 flights, 7 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 7 points of difference.
One caution: this is a thin sample. 503 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. 503 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 74.7% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 501 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
- SkyWest Airlines on SFO to SLC75.9%
- Delta Air Lines on SFO to SLC75.7%
- Frontier Airlines on SFO to SLC65.8%
- 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 7.05 million flight records
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.