Carrier route record
UASLC→SFO
United Airlines · Salt Lake City to San Francisco
- Flights
- 504
- 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 SLC to SFO sits in the middle of the pack with a C+. About seven flights in ten arrive on time by the DOT's definition, 9 points worse than the national rate of 77.3%. The late ones land a little over an hour behind schedule. That rests on 504 flights. The strongest carrier on the route with a full sample, SkyWest Airlines, flew 1,011 at 63.9% on time.
The national on-time rate over the same period is 77.3%, so United on SLC to SFO runs 9 points behind the country as a whole. Across a thousand flights that is about 91 extra late arrivals.
Key figures
On time
68.2%
Arrivals under 15 minutes late, of 503 completed flights
Avg delay
70 min
Across delayed arrivals only, not all flights
Cancelled
0.20%
National rate is 1.89%
Whole route
63.4%
Every carrier on SLC to SFO, 3,433 flights
These figures cover 504 flights between September 2025 and August 2026. Beyond the headline rate, 13.3% 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 SLC to SFO
United flew 504 of the 3,433 flights on SLC to SFO, about 15% of it. Its 68.2% on time is 5 points better than the route as a whole, which runs 63.4%. Ranked by on-time rate it is first of four carriers on the route, where the range runs from United at 68.2% to Delta at 61.6%. One of those carriers flew fewer than 365 flights here, so treat their positions as rough.
The two carriers here are closely matched: 2 points 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) | 504 | 68.2% | 70 min | 0.20% | C+ |
| Frontier Airlinesthin sample | 206 | 65.2% | 97 min | 2.43% | C |
| SkyWest Airlines | 1,011 | 63.9% | 75 min | 1.19% | D |
| Delta Air Lines | 1,712 | 61.6% | 52 min | 0.93% | D+ |
No carrier stands out. SkyWest tops the table at 63.9%, 2 points 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 54 points, against 2 points between the best and worst carrier.
- 5am–8am5 flights—
- 8am–11am57 flights73.7%
- 11am–2pm110 flights88.2%
- 2pm–5pm223 flights72.6%
- 5pm–8pm—
- 8pm–5am109 flights34.3%
Scale runs 25% to 95%. Rows with fewer than 30 flights show a dash.
The 8pm–5am window is where this operation falls apart: 34.3% on time, against 88.2% 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 223 flights scheduled in it.
Across the year
United on SLC to SFO through the year
July is the worst month at 29.6% on time, 61 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, Saturday is the strongest day at 78.0% on time and Monday the weakest at 59.0%, a spread of 19 points.
Arrival by arrival
How late United on SLC to SFO runs when it is late
United on SLC to SFO often beats the schedule: 186 of 503 completed flights, 37%, arrived 15 minutes or more early. The 160 late arrivals split 36 under half an hour, 57 between 30 and 60 minutes, and 67 an hour or more.
- 15+ min early186 flights37.0%
- Within 15 min157 flights31.2%
- 15–29 min late36 flights7.2%
- 30–59 min late57 flights11.3%
- 1–2 hours late44 flights8.7%
- 2+ hours late23 flights4.6%
Scale runs 0% to 100%.
Share of 503 completed flights by arrival against schedule.
Time lost at the gate mostly stays lost. Of 155 departures that left 15 minutes late or more, only 14 made it up before arrival. 19 flights left on time and still arrived late.
The worst days
Worst days for United on SLC to SFO
The latest arrival of the period was on 29 May 2026, 5 hours 35 minutes behind schedule; most of its delay minutes were filed as a late-arriving aircraft. Three of the five worst days fell in June 2026.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 29 May 2026 | 5 hours 35 minutes | Late-arriving aircraft |
| 5 November 2025 | 4 hours 14 minutes | National Airspace System |
| 8 June 2026 | 3 hours 59 minutes | Late-arriving aircraft |
| 11 June 2026 | 3 hours 38 minutes | Late-arriving aircraft |
| 19 June 2026 | 3 hours 36 minutes | Late-arriving aircraft |
Delay causes
Why United runs late on this route
National Airspace System accounts for 59% of the 11,000 delay minutes carriers reported here, and the remaining four split what is left.
- 59%National Airspace System
- 31%Late-arriving aircraft
- 9%Carrier
- 0%Extreme weather
59% 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 6,602 minutes out of 11,000, against a national NAS share of 21%. The split is drawn from 11,137 reported delay minutes.
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
13.3% of arrivals land a full hour or more behind schedule, against 8.3% nationally. Ninety minutes is the honest minimum for a connection 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.
The return leg is a different operation and performs like one: it runs 74.7% on time across 503 flights, 7 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 7 points of difference.
One caution: this is a thin sample. 504 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. 504 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 68.2% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 503 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
- Frontier Airlines on SLC to SFO65.2%
- SkyWest Airlines on SLC to SFO63.9%
- Delta Air Lines on SLC to SFO61.6%
- United Airlines network-wide record
- Salt Lake City International (SLC) delay statistics
- San Francisco International (SFO) delay statistics
- How often a connection fails at the major US hubs
- 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.