Flight number record
DL 1331
Delta Air Lines · San Francisco to Salt Lake City
- Route
- SFO → SLC
- Departs
- 06:00
- Flights
- 365
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s DL 1331, check with Delta Air Lines.
DL 1331 earns an A+. Nearly every flight arrives inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 19 points better than the national rate of 77.3%. When something does go wrong the average delay runs close to two hours. That rests on 365 flights, with a median arrival 14 minutes early.
Set against the rest of the country, DL 1331's record is 19 points better than the US average of 77.3%. That gap is worth roughly 188 fewer late arrivals for every thousand flights.
Key figures
On time
96.1%
Arrivals under 15 minutes late, of 363 completed flights
Avg delay
109 min
Across delayed arrivals only, not all flights
Cancelled
0.55%
National rate is 1.89%
1 hour+ late
1.7%
National rate is 8.3%
These figures cover 365 flights between September 2025 and August 2026. The median arrival is 14 minutes early, which is the part an average hides: most flights here are fine, and the on-time rate is decided by a tail of badly late ones. On-time means under 15 minutes late, the DOT's own threshold.
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Schedule
When DL 1331 flies
DL 1331 flies SFO to SLC without a single fixed slot. Its most common scheduled departure was 06:00, used on 107 of 365 flights, with 05:40 (91 flights) and 05:50 (86 flights) next.
- Departs 06:00107 flights29.3%
- Departs 05:4091 flights24.9%
- Departs 05:5086 flights23.6%
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 06:00 departure sits in the 5am–8am window. Across every US flight scheduled in that window the on-time rate is 89.3%, and DL 1331 runs 7 points better at 96.1%. Early departures usually start with an aircraft that has not flown yet that day, which is most of why the window does well.
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Against the route
DL 1331 next to SFO to SLC
Every carrier on SFO to SLC combined arrived on time 75.0% of the time across 3,431 flights, so DL 1331 is 21 points ahead of it. Delta flew 1,714 flights on the same city pair under all its flight numbers, including this one, and those ran 75.7% on time. Across its whole network Delta Air Lines managed 81.1%, which this flight beats by 15 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| DL 1331 | 365 | 96.1% | 109 min | 0.55% | A+ |
| All Delta Air Lines on SFO–SLC | 1,714 | 75.7% | 74 min | 0.93% | B+ |
| All carriers on SFO–SLC | 3,431 | 75.0% | 70 min | 1.02% | B |
| Delta Air Lines, whole network | 1,039,517 | 81.1% | 71 min | 1.74% | B |
Across the year
DL 1331 quarter by quarter
Quarter by quarter DL 1331 held fairly steady: 96.7% in Jul–Sep 2025, 96.7% in Oct–Dec 2025, 96.6% in Jan–Mar 2026, 96.7% in Apr–Jun 2026 and 93.5% in Jul–Sep 2026. A spread of 3 points is about what a sample of this size moves on its own, so the annual figure is a fair summary.
- Jul–Sep 202530 flights96.7%
- Oct–Dec 202592 flights96.7%
- Jan–Mar 202690 flights96.6%
- Apr–Jun 202691 flights96.7%
- Jul–Sep 202662 flights93.5%
Scale runs 85% to 100%.
By weekday, DL 1331 ranged from 90.4% on Tuesday to 100.0% on Thursday. With about 52 flights behind each day, a spread of 10 points is inside normal variation, so the day you fly is not worth changing for this flight.
Arrival by arrival
How late DL 1331 runs when it is late
DL 1331 often beats the schedule: 174 of 363 completed flights, 48%, arrived 15 minutes or more early. The 14 late arrivals split 6 under half an hour, 2 between 30 and 60 minutes, and 6 an hour or more.
- 15+ min early174 flights47.9%
- Within 15 min175 flights48.2%
- 15–29 min late6 flights1.7%
- 30–59 min late2 flights0.6%
- 1–2 hours late3 flights0.8%
- 2+ hours late3 flights0.8%
Scale runs 0% to 100%.
Share of 363 completed flights by arrival against schedule.
Only 16 of 363 completed flights left 15 minutes late or more, too few to say how often the time is made up.
The worst days
Worst days for DL 1331
The latest arrival of the period was on 22 June 2026, 10 hours 23 minutes behind schedule; most of its delay minutes were filed as a late-arriving aircraft. On three of the five worst days the largest share was filed as carrier-caused (crew, maintenance, fuelling, baggage).
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 22 June 2026 | 10 hours 23 minutes | Late-arriving aircraft |
| 10 February 2026 | 4 hours 7 minutes | Carrier |
| 23 December 2025 | 3 hours 5 minutes | Late-arriving aircraft |
| 10 July 2026 | 1 hour 53 minutes | Carrier |
| 28 February 2026 | 1 hour 19 minutes | Carrier |
Delay causes
Why DL 1331 runs late
Late-arriving aircraft accounts for 53% of the 1,526 delay minutes carriers reported here, and the remaining four split what is left.
- 53%Late-arriving aircraft
- 40%Carrier
- 8%National Airspace System
53% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 1,526 reported delay minutes here, that single category outweighs weather by 53 to one. The split is drawn from 1,526 delay minutes reported on DL 1331.
Cancellations are rare at 0.55%, 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 routes
What a delay on this flight costs
Badly late arrivals are rare here: only 1.7% land an hour or more behind schedule, against 8.3% nationally. Connections built on this flight are about as safe as US domestic connections get, though a cancelled flight still ignores every layover you give it.
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.
Every one of the 365 flights under DL 1331 in the data flew SFO to SLC. The number was not reused on any other city pair, which makes this a clean record of one route.
One caution: this is a thin sample. 365 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 DL 1331
For a booking, DL 1331 has one of the better records a US domestic flight can show: 96.1% on time and 0.55% cancelled. That is a base rate, not a promise about any single day.
Related
Where to go next
- SFO to SLC, every carrier and departure
- SLC to SFO, the return direction
- Delta Air Lines 920 on the same route76.1%
- Delta Air Lines 1088 on the same route65.4%
- Delta Air Lines 902 on the same route65.4%
- San Francisco International (SFO) delay statistics
- Salt Lake City International (SLC) 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
- Why the first flight of the morning is statistically safest
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.