Carrier route record
DLSLC→SFO
Delta Air Lines · Salt Lake City to San Francisco
- Flights
- 1,712
- Period
- September 2025 to August 2026
- Share of route
- 50%
- Carriers
- 4
Historical statistics for September 2025 to August 2026, not live status. For today’s flights, check with Delta Air Lines.
Delta on SLC to SFO draws a D+. Roughly one flight in three arrives at least 15 minutes late, and the typical late arrival is roughly 50 minutes behind schedule. Build slack into anything you connect to. That rests on 1,712 flights. The strongest carrier on the route with a full sample, United Airlines, flew 504 at 68.2% on time.
The national on-time rate over the same period is 77.3%, so Delta on SLC to SFO runs 16 points behind the country as a whole. Across a thousand flights that is about 157 extra late arrivals.
Key figures
On time
61.6%
Arrivals under 15 minutes late, of 1,694 completed flights
Avg delay
52 min
Across delayed arrivals only, not all flights
Cancelled
0.93%
National rate is 1.89%
Whole route
63.4%
Every carrier on SLC to SFO, 3,433 flights
These figures cover 1,712 flights between September 2025 and August 2026. Beyond the headline rate, 9.7% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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Carrier by carrier
Delta against every carrier on SLC to SFO
Delta flew 1,712 of the 3,433 flights on SLC to SFO, about 50% of it. Its 61.6% on time is 2 points worse than the route as a whole, which runs 63.4%. Ranked by on-time rate it is last 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: 4 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 | 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 (this page) | 1,712 | 61.6% | 52 min | 0.93% | D+ |
No carrier stands out. United tops the table at 68.2%, 4 points clear of the bottom, which is inside the range this kind of sample moves year to year.
Flight by flight
Delta flight numbers on SLC to SFO
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Departure window
When Delta runs best on this route
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 21 points, against 4 points between the best and worst carrier.
- 5am–8am224 flights68.3%
- 8am–11am138 flights57.0%
- 11am–2pm365 flights59.8%
- 2pm–5pm353 flights62.4%
- 5pm–8pm102 flights77.8%
- 8pm–5am530 flights57.6%
Scale runs 50% to 85%.
The 5pm–8pm window is the strongest at 77.8% on time. The full set of windows spans 21 points.
Across the year
Delta on SLC to SFO through the year
July is the worst month at 31.5% on time, 53 points below March, the best at 84.9%. 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 149 flights.
Across the week, Tuesday is the strongest day at 69.8% on time and Monday the weakest at 55.7%, a spread of 14 points.
Arrival by arrival
How late Delta on SLC to SFO runs when it is late
The 651 late arrivals split 238 under half an hour, 248 between 30 and 60 minutes, and 165 an hour or more.
- 15+ min early272 flights16.1%
- Within 15 min771 flights45.5%
- 15–29 min late238 flights14.0%
- 30–59 min late248 flights14.6%
- 1–2 hours late120 flights7.1%
- 2+ hours late45 flights2.7%
Scale runs 0% to 100%.
Share of 1,694 completed flights by arrival against schedule.
Time lost at the gate mostly stays lost. Of 466 departures that left 15 minutes late or more, only 43 made it up before arrival. In the other direction, 228 flights left on time yet arrived 15 minutes late or more, so that delay built up after pushback: in the air, in a holding pattern or on the ground at SFO.
The worst days
Worst days for Delta on SLC to SFO
The latest arrival of the period was on 21 June 2026, 15 hours 34 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). The five worst days are spread across June, December, July and April, with no single month standing out.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 21 June 2026 | 15 hours 34 minutes | Carrier |
| 22 December 2025 | 8 hours 21 minutes | Carrier |
| 9 July 2026 | 4 hours 19 minutes | National Airspace System |
| 2 April 2026 | 4 hours 9 minutes | Late-arriving aircraft |
| 27 April 2026 | 3 hours 57 minutes | Late-arriving aircraft |
Delay causes
Why Delta runs late on this route
National Airspace System accounts for 57% of the 34,000 delay minutes carriers reported here, and the remaining four split what is left.
- 57%National Airspace System
- 26%Carrier
- 16%Late-arriving aircraft
- 1%Extreme weather
57% 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 19,000 minutes out of 34,000, against a national NAS share of 21%. The split is drawn from 33,506 reported delay minutes.
Cancellations sit at 0.93% against a national 1.89%, which is ordinary. Diversions add another 0.12%.
Connections and stage length
What a delay here costs
9.7% 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 75.7% on time across 1,714 flights, 14 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 14 points of difference.
The sample behind these figures is 1,712 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.
What to do with this
Booking Delta on SLC to SFO
Put together: the calendar is the biggest lever here, not the carrier or the hour. March runs 84.9% on time and July 31.5%, a swing of 53 points. If the dates move at all, move them out of July before you think about anything else. 1,694 completed flights over 12 months sit behind that.
Related
Where to go next
- SLC to SFO, every carrier
- Delta on SFO to SLC, the return leg
- United Airlines on SLC to SFO68.2%
- Frontier Airlines on SLC to SFO65.2%
- SkyWest Airlines on SLC to SFO63.9%
- Delta Air Lines network-wide record
- Salt Lake City International (SLC) delay statistics
- San Francisco International (SFO) delay statistics
- The best time of day to fly, according to 7.05 million flight records
- How often a connection fails at the major US hubs
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.