Flight number record
DL 1088
Delta Air Lines · Salt Lake City to San Francisco
- Route
- SLC → SFO
- Departs
- 15:00
- Flights
- 364
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s DL 1088, check with Delta Air Lines.
DL 1088 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 364 flights, with a median arrival 3 minutes late.
The national on-time rate over the same period is 77.3%, so DL 1088 runs 14 points behind the country as a whole. Across a thousand flights that is about 143 extra late arrivals.
Key figures
On time
63.0%
Arrivals under 15 minutes late, of 359 completed flights
Avg delay
56 min
Across delayed arrivals only, not all flights
Cancelled
1.10%
National rate is 1.89%
1 hour+ late
11.7%
National rate is 8.3%
These figures cover 364 flights between September 2025 and August 2026. Beyond the headline rate, 11.7% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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Schedule
When DL 1088 flies
DL 1088 flies SLC to SFO without a single fixed slot. Its most common scheduled departure was 15:00, used on 179 of 364 flights.
- Departs 15:00179 flights49.2%
Scale runs 0% to 100%.
Share of scheduled departures at each local time. Times used on fewer than one flight in ten are not listed.
A 15:00 departure sits in the 2pm–5pm window. Across every US flight scheduled in that window the on-time rate is 71.9%, and DL 1088 runs 9 points worse at 63.0%. Midday slots inherit some of the morning's delays without yet carrying the full weight of the evening's.
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Against the route
DL 1088 next to SLC to SFO
Every carrier on SLC to SFO combined arrived on time 63.4% of the time across 3,433 flights, so DL 1088 is about level with it. Delta flew 1,712 flights on the same city pair under all its flight numbers, including this one, and those ran 61.6% on time. Across its whole network Delta Air Lines managed 81.1%, which this flight trails by 18 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| DL 1088thin sample | 364 | 63.0% | 56 min | 1.10% | D |
| All Delta Air Lines on SLC–SFO | 1,712 | 61.6% | 52 min | 0.93% | D+ |
| All carriers on SLC–SFO | 3,433 | 63.4% | 63 min | 0.99% | D+ |
| Delta Air Lines, whole network | 1,039,517 | 81.1% | 71 min | 1.74% | B |
Across the year
DL 1088 quarter by quarter
DL 1088 did not run the same all year. Its best quarter was Jul–Sep 2025 at 86.7% on time and its weakest Apr–Jun 2026 at 45.6%, a swing of 41 points on roughly 73 flights a quarter. The twelve-month rate averages over that, so if you are flying in a weak quarter the quarter's own figure is the better guide.
- Jul–Sep 202530 flights86.7%
- Oct–Dec 202591 flights71.1%
- Jan–Mar 202690 flights72.7%
- Apr–Jun 202691 flights45.6%
- Jul–Sep 202662 flights50.8%
Scale runs 35% to 90%.
By weekday, DL 1088 did best on Tuesday at 76.5% on time and worst on Sunday at 57.7%. Each day rests on about 52 flights, so a gap of 19 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late DL 1088 runs when it is late
The 133 late arrivals split 40 under half an hour, 51 between 30 and 60 minutes, and 42 an hour or more.
- 15+ min early64 flights17.8%
- Within 15 min162 flights45.1%
- 15–29 min late40 flights11.1%
- 30–59 min late51 flights14.2%
- 1–2 hours late30 flights8.4%
- 2+ hours late12 flights3.3%
Scale runs 0% to 100%.
Share of 359 completed flights by arrival against schedule.
Time lost at the gate mostly stays lost. Of 104 departures that left 15 minutes late or more, only 9 made it up before arrival. In the other direction, 38 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 DL 1088
The latest arrival of the period was on 9 July 2026, 4 hours 19 minutes behind schedule; most of its delay minutes were filed as national airspace system delay. The five worst days are spread across July, January, August and September, with no single month standing out.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 9 July 2026 | 4 hours 19 minutes | National Airspace System |
| 3 January 2026 | 3 hours 26 minutes | National Airspace System |
| 3 August 2026 | 2 hours 52 minutes | Late-arriving aircraft |
| 30 January 2026 | 2 hours 51 minutes | Carrier |
| 20 September 2025 | 2 hours 50 minutes | Carrier |
Delay causes
Why DL 1088 runs late
National Airspace System accounts for 49% of the 7,445 delay minutes carriers reported here, and the remaining four split what is left.
- 49%National Airspace System
- 26%Carrier
- 23%Late-arriving aircraft
- 1%Extreme weather
49% 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 3,680 minutes out of 7,445, against a national NAS share of 21%. The split is drawn from 7,445 delay minutes reported on DL 1088.
Cancellations sit at 1.10% against a national 1.89%, which is ordinary. Diversions add another 0.27%.
Connections and routes
What a delay on this flight costs
11.7% 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.
DL 1088 is not only a SLC to SFO flight. It also flew SFO to SLC (358 flights, 65.4% on time) often enough to be scored on its own. Airlines attach one number to several legs of an aircraft's day, and each leg keeps its own record here, so check which city pair is on your booking before reading a rate.
One caution: this is a thin sample. 364 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.
| Also flown as | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| SFO to SLCthin sample | 358 | 65.4% | 83 min | 1.12% | C |
What to do with this
Booking DL 1088
For a booking, read DL 1088 as 63.0% on time with 1.10% cancelled over 364 flights. Those are rates from the past twelve months, not a forecast for any particular day.
Related
Where to go next
- SLC to SFO, every carrier and departure
- SFO to SLC, the return direction
- Delta Air Lines 902 on the same route59.8%
- Delta Air Lines 920 on the same route63.9%
- Delta Air Lines 1091 on the same route65.3%
- Delta Air Lines 2762 on the same route53.2%
- Salt Lake City International (SLC) delay statistics
- San Francisco International (SFO) delay statistics
- Delta Air Lines on-time record
- Every Delta Air Lines flight number with a record
- The most and least reliable flight numbers in the US
- How often a connection fails at the major US hubs
A flight number here means Delta Air Lines’s own number as it reports to the DOT. How the figures are computed is on the methodology page.
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.