Route reliability record
SLC→SFO
Salt Lake City to San Francisco
- Flights
- 3,433
- Period
- September 2025 to August 2026
- Distance
- 599 mi
- Carriers
- 4
This route draws a D+. Roughly one flight in three arrives at least 15 minutes late, and the typical late arrival is about an hour behind schedule. Build slack into anything you connect to. That rests on 3,433 SLC to SFO flights, of which United Airlines flew 504 at 68.2% on time.
Best time to fly SLC to SFO: a 5am–8am departure, ideally on a Saturday. Flights in that window arrived on time 80.5% of the time and Saturday flights 73.1%, against 63.4% for the route overall.
United Airlines is the most reliable of the three carriers covered here at 68.2% on time across 504 flights.
Key figures
On time
63.4%
Arrivals under 15 minutes late, of 3,395 completed flights
Avg delay
63 min
Across delayed arrivals only, not all flights
Cancelled
0.99%
National rate is 1.89%
Best carrier
United
68.2% on time across 504 flights
These figures cover 3,433 flights between September 2025 and August 2026. Beyond the headline rate, 11.8% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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Carrier by carrier
Which airline is most reliable on SLC to SFO
The choice of carrier is not cosmetic here. United Airlines arrives on time 68.2% of the time; Delta Air Lines manages 61.6%. Sample sizes sit next to every figure, because a two-point gap across 1,712 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| United Airlines | 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+ |
United leads Delta by 7 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.
Flight by flight
Flights on SLC to SFO
The flight numbers below flew this route at least 250 times in the period, busiest first. Each has its own record, with its schedule and delay causes.
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Best ways to make this trip
The most reliable ways to fly Salt Lake City to San Francisco
Every airline on this route and on the routes between nearby airports, ranked by how often a scheduled flight actually operated and arrived on time. 4 of the top 5 use a different airport at one end.
| Option | Airline | Success | On time | Cancelled | Best departure | Most punctual flight |
|---|---|---|---|---|---|---|
| 1. SLC → SJCSalt Lake City to San Jose | SkyWest Airlines | 91.9% | 92.0% | 0.15% | 8am–11am, Tue | — |
| 2. SLC → OAKSalt Lake City to Oakland | SkyWest Airlines | 91.6% | 91.8% | 0.19% | 11am–2pm, Tue | OO 3797 22:50 |
| 3. SLC → OAKSalt Lake City to Oakland | Southwest Airlines | 86.8% | 87.0% | 0.18% | 5am–8am, Tue | — |
| 4. SLC → SJCSalt Lake City to San Jose | Delta Air Lines | 85.3% | 85.7% | 0.43% | 11am–2pm, Tue | DL 1272 22:50 |
| 5. SLC → SFOSalt Lake City to San Francisco | United Airlines | 68.1% | 68.2% | 0.20% | 11am–2pm, Sat | — |
Success is the share of scheduled flights that operated and arrived less than 15 minutes late, so a cancelled flight counts against it. “(route)” means the best time comes from every carrier on the route rather than this airline alone.
Departure window
The best time of day to leave
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 32 points, against 7 points between the best and worst carrier.
- 5am–8am505 flights80.5%
- 8am–11am440 flights48.2%
- 11am–2pm605 flights65.1%
- 2pm–5pm842 flights68.1%
- 5pm–8pm202 flights73.2%
- 8pm–5am839 flights53.0%
Scale runs 40% to 85%.
Book the early departure. Flights leaving between 5am–8am arrive on time 80.5% of the time, against 48.2% for the morning window. That is 32 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 842 flights scheduled in it.
Explore
Filter SLC to SFO by airline, time, month and day
Pick a breakdown and a carrier. The dashed mark on each row is the same slice for every US flight.
On SLC to SFO, the best departure window is 5am–8am at 80.5% on time and the worst is 8am–11am at 48.2%, a wide gap of 32.3 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am80.5%
- 8–11am48.2%
- 11am–2pm65.1%
- 2–5pm68.1%
- 5–8pm73.2%
- 8pm–5am53.0%
best all US flightsScale 40% to 95%.
Across the year
When delays peak on this route
This route's year swings by 44 points from best month to worst, which is wide. An annual average tells you very little about the week you are actually flying, so read the strip rather than the headline if your dates are fixed.
July is the worst month at 39.7% on time, 44 points below March, the best at 83.9%. 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. March was the busiest month here, with 325 flights.
Across the week, Saturday is the strongest day at 73.1% on time and Monday the weakest at 56.0%, a spread of 17 points.
Delay causes
Why this route gets delayed
National Airspace System accounts for 55% of the 79,000 delay minutes carriers reported here, and the remaining four split what is left.
- 55%National Airspace System
- 24%Carrier
- 20%Late-arriving aircraft
- 1%Extreme weather
55% 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 43,000 minutes out of 79,000, against a national NAS share of 21%. The split is drawn from 78,594 reported delay minutes.
Cancellations sit at 0.99% against a national 1.89%, which is ordinary. Diversions add another 0.12%.
Connections and stage length
What a delay here actually costs
11.8% 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 75.0% on time across 3,431 flights, 12 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 12 points of difference.
The sample behind these figures is 3,433 flights, enough that the headline rate is stable to within roughly a point. The hour-block and month splits divide that further, so read the thinner bars with more caution than the headline.
Work out the risk of missing a connection in SFO after this flight
What to do with this
Booking this route
Put together: the calendar is the biggest lever here, not the carrier or the hour. March runs 83.9% on time and July 39.7%, a swing of 44 points. If the dates move at all, move them out of July before you think about anything else. 3,395 completed flights over 12 months sit behind that.
Common questions
SLC to SFO questions
How often is SLC to SFO delayed?
Roughly one flight in three arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 36.6% of the 3,433 flights in this analysis, against 22.7% nationally. Delayed flights are late by about an hour on average.
Which airline is most reliable on SLC to SFO?
United Airlines leads at 68.2% on time across 504 flights. Delta Air Lines is at the other end on 61.6%, a gap of 7 points. Sample size matters as much as the percentage: a rate built from a few hundred flights moves around far more than one built from ten thousand.
What time of day has the fewest delays on SLC to SFO?
The 5am–8am departure window is the strongest at 80.5% on time. The 8am–11am window is the weakest at 48.2%, 32 points behind. Later departures inherit delays from earlier flights the same aircraft has already flown, which is why the curve slopes the way it does.
How bad are July delays on SLC to SFO?
July is the weakest month at 39.7% on time, compared with 83.9% in March. Across the year that is 44 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.
Related
Where to go next
- SFO to SLC — the return legseparate record
- Salt Lake City International (SLC) delay statistics
- San Francisco International (SFO) delay statistics
- United Airlines on SLC to SFO68.2%
- Frontier Airlines on SLC to SFO65.2%
- SkyWest Airlines on SLC to SFO63.9%
- Delta Air Lines on SLC to SFO61.6%
- SLC to DEN, a related route79.0%
- LAX to SFO, a related route60.1%
- SLC to PHX, a related route83.5%
- United Airlines on-time record68.2%
- Frontier Airlines on-time record65.2%
- SkyWest Airlines on-time record63.9%
- How often a connection fails at the major US hubs
- The best time of day to fly, according to 7.05 million flight records
Direction matters. SLC to SFO and SFO to SLC are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
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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.