Carrier route record

DLSFO→SLC

Delta Air Lines · San Francisco to Salt Lake City

Flights: 1,714
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 SFO to SLC sits in the middle of the pack with a B+. Close to three flights in four arrive on time by the DOT's definition, 2 points worse than the national rate of 77.3%. The late ones land a little over an hour behind schedule. That rests on 1,714 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 Delta on SFO to SLC from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.

On time

75.7%

Arrivals under 15 minutes late, of 1,697 completed flights

Avg delay

74 min

Across delayed arrivals only, not all flights

Cancelled

0.93%

National rate is 1.89%

Whole route

75.0%

Every carrier on SFO to SLC, 3,431 flights

These figures cover 1,714 flights between September 2025 and August 2026. Beyond the headline rate, 8.1% 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 SFO to SLC

Delta flew 1,714 of the 3,431 flights on SFO to SLC, about 50% of it. Its 75.7% on time is about level with the route as a whole at 75.0%. Ranked by on-time rate it is number two 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: 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.

On-time performance by carrier on SFO to SLC
Airline	Flights	On time	Avg delay	Cancelled	Grade
SkyWest Airlines	1,008	75.9%	68 min	1.39%	B
Delta Air Lines (this page)	1,714	75.7%	74 min	0.93%	B+
United Airlines	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%, about a point clear of the bottom, which is inside the range this kind of sample moves year to year.

Flight by flight

Delta flight numbers on SFO to SLC

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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 32 points, against about a point between the best and worst carrier.

5am–8am365 flights96.1%
8am–11am361 flights76.1%
11am–2pm366 flights63.8%
2pm–5pm1 flights—
5pm–8pm621 flights70.5%
8pm–5am—

Scale runs 55% to 100%. Rows with fewer than 30 flights show a dash.

The weak window here is the middle of the day, not the evening: 11am–2pm runs 63.8% on time against 96.1% for 5am–8am. That shape usually means a departure bank rather than an accumulating delay, so the recovery later in the afternoon is real rather than noise. The 5pm–8pm window is the busiest, with 621 flights scheduled in it.

Across the year

Delta on SFO to SLC through the year

Darker means more delays. Figures are on-time percentages.March best, June worst

June is the worst month at 61.7% on time, 27 points below March, the best at 88.4%. 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. March was the busiest month here, with 149 flights.

Across the week, Tuesday is the strongest day at 82.4% on time and Monday the weakest at 70.9%, a spread of 12 points.

Arrival by arrival

How late Delta on SFO to SLC runs when it is late

Delta on SFO to SLC often beats the schedule: 524 of 1,697 completed flights, 31%, arrived 15 minutes or more early. The 412 late arrivals split 149 under half an hour, 125 between 30 and 60 minutes, and 138 an hour or more.

15+ min early524 flights30.9%
Within 15 min761 flights44.8%
15–29 min late149 flights8.8%
30–59 min late125 flights7.4%
1–2 hours late91 flights5.4%
2+ hours late47 flights2.8%

Scale runs 0% to 100%.

Share of 1,697 completed flights by arrival against schedule.

92 of 465 late departures made up the time and arrived on time, 20% of them. 39 flights left on time and still arrived late.

The worst days

Worst days for Delta on SFO to SLC

The latest arrival of the period was on 5 April 2026, 16 hours 59 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). Three of the five worst days fell in April 2026.

The latest arrivals of Delta on SFO to SLC in the period
Date	Arrived late by	Largest filed cause
5 April 2026	16 hours 59 minutes	Carrier
6 April 2026	16 hours 59 minutes	Carrier
2 April 2026	15 hours 52 minutes	Carrier
19 March 2026	14 hours 32 minutes	Carrier
23 December 2025	14 hours 29 minutes	Carrier

Delay causes

Why Delta runs late on this route

Late-arriving aircraft accounts for 59% of the 30,000 delay minutes carriers reported here, and the remaining four split what is left.

Late-arriving aircraft
59%
Carrier
33%
National Airspace System
7%
Security
1%
Extreme weather
1%

59% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 30,000 reported delay minutes here, that single category outweighs weather by 59 to one. The split is drawn from 30,410 reported delay minutes.

The practical consequence: the 5am–8am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 96.1% on time here.

Cancellations sit at 0.93% against a national 1.89%, which is ordinary. Diversions add another 0.06%.

Connections and stage length

What a delay here costs

8.1% 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 a little over 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 61.6% on time across 1,712 flights, 14 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 14 points of difference.

The sample behind these figures is 1,714 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 SFO to SLC

Put together: the calendar is the biggest lever here, not the carrier or the hour. March runs 88.4% on time and June 61.7%, a swing of 27 points. If the dates move at all, move them out of June before you think about anything else. 1,697 completed flights over 12 months sit behind that.

Where to go next

Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated 22 October 2026; recomputed monthly. How this data is collected.

Key figures