Flight number record
DL 1120
Delta Air Lines · Seattle to Salt Lake City
- Route
- SEA → SLC
- Departs
- 13:30
- Flights
- 365
- Period
- July 2025 to June 2026
Historical statistics for July 2025 to June 2026, not live status. For today’s DL 1120, check with Delta Air Lines.
DL 1120 lands a B+, 5 points better than the national rate of 77.6%. About one flight in six arrives 15 minutes late or worse, and those flights are late by about an hour on average. That is a workable record, not a spotless one. That rests on 365 flights, with a median arrival 7 minutes early.
Set against the rest of the country, DL 1120's record is 5 points better than the US average of 77.6%. That gap is worth roughly 47 fewer late arrivals for every thousand flights.
Key figures
On time
82.3%
Arrivals under 15 minutes late, of 362 completed flights
Avg delay
60 min
Across delayed arrivals only, not all flights
Cancelled
0.55%
National rate is 1.81%
1 hour+ late
5.0%
National rate is 8.1%
These figures cover 365 flights between July 2025 and June 2026. The median arrival is 7 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.
Schedule
When DL 1120 flies
DL 1120 flies SEA to SLC without a single fixed slot. Its most common scheduled departure was 13:30, used on 175 of 365 flights, with 13:38 (59 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.
- Departs 13:30175 flights47.9%
- Departs 13:3859 flights16.2%
Scale runs 0% to 100%. Rows with fewer than 30 flights show a dash.
Share of scheduled departures at each local time. Times used on fewer than one flight in ten are not listed.
A 13:30 departure sits in the 11am–2pm window. Across every US flight scheduled in that window the on-time rate is 78.8%, and DL 1120 runs 4 points better at 82.3%. Midday slots inherit some of the morning's delays without yet carrying the full weight of the evening's.
Against the route
DL 1120 next to SEA to SLC
Every carrier on SEA to SLC combined arrived on time 83.6% of the time across 4,107 flights, so DL 1120 is about level with it. Delta flew 2,219 flights on the same city pair under all its flight numbers, including this one, and those ran 87.0% on time. Across its whole network Delta Air Lines managed 81.6%, close to this flight's figure.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| DL 1120 | 365 | 82.3% | 60 min | 0.55% | B+ |
| All Delta Air Lines on SEA–SLC | 2,219 | 87.0% | 58 min | 0.54% | A+ |
| All carriers on SEA–SLC | 4,107 | 83.6% | 50 min | 0.93% | B+ |
| Delta Air Lines, whole network | 1,038,570 | 81.6% | 71 min | 1.62% | B |
Across the year
DL 1120 quarter by quarter
Quarter by quarter DL 1120 held fairly steady: 77.8% in Jul–Sep 2025, 82.6% in Oct–Dec 2025, 83.1% in Jan–Mar 2026 and 85.7% in Apr–Jun 2026. A spread of 8 points is about what a sample of this size moves on its own, so the annual figure is a fair summary.
- Jul–Sep 202592 flights77.8%
- Oct–Dec 202592 flights82.6%
- Jan–Mar 202690 flights83.1%
- Apr–Jun 202691 flights85.7%
Scale runs 70% to 90%. Rows with fewer than 30 flights show a dash.
By weekday, DL 1120 did best on Wednesday at 88.5% on time and worst on Thursday at 75.0%. Each day rests on about 52 flights, so a gap of 14 points is worth noticing but could still narrow in another year.
Delay causes
Why DL 1120 runs late
One category carries most of the weight here. Carrier accounts for 63% of the 3,867 delay minutes carriers reported, and the remaining four split what is left. The split is by minutes rather than by flights, so a few very long delays count for as much as many short ones.
- 63%Carrier
- 32%Late-arriving aircraft
- 5%National Airspace System
The largest share of delay minutes, 63%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. Unlike weather, that is a management outcome, and it is the category where the gap between two carriers on the same schedule is genuinely earned. It accounts for 2,420 of the 3,867 delay minutes reported here. The split is drawn from 3,867 delay minutes reported on DL 1120.
Cancellations are rare at 0.55%, below the national 1.81% 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
5.0% of arrivals land an hour or more late, close to the national 8.1%. That is the figure that decides a connection, and it says a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last about an hour, which a normal layover absorbs.
The 689 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. It is also long enough that the aircraft usually flies three or four legs a day rather than six, which slows how fast delay compounds.
Every one of the 365 flights under DL 1120 in the data flew SEA 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 1120
For a booking, read DL 1120 as 82.3% on time with 0.55% cancelled over 365 flights. Those are rates from the past twelve months, not a forecast for any particular day.
Related
Where to go next
- SEA to SLC, every carrier and departure
- SLC to SEA, the return direction
- Delta Air Lines 1128 on the same route94.2%
- Delta Air Lines 1016 on the same route90.5%
- Delta Air Lines 1265 on the same route86.0%
- Delta Air Lines 1165 on the same route79.0%
- SkyWest Airlines 3298 on the same route80.5%
- Alaska Airlines 733 on the same route66.2%
- Seattle-Tacoma International (SEA) 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, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.