Flight number record
DL 1120
Delta Air Lines · Seattle to Salt Lake City
- Route
- SEA → SLC
- Departs
- 13:30
- Flights
- 365
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s DL 1120, check with Delta Air Lines.
DL 1120 lands a B+, 6 points better than the national rate of 77.3%. About one flight in six arrives 15 minutes late or worse, and those flights are late by about an hour on average. That rests on 365 flights, with a median arrival 7 minutes early.
Set against the rest of the country, DL 1120's record is 6 points better than the US average of 77.3%. That gap is worth roughly 57 fewer late arrivals for every thousand flights.
Key figures
On time
83.0%
Arrivals under 15 minutes late, of 364 completed flights
Avg delay
64 min
Across delayed arrivals only, not all flights
Cancelled
0.27%
National rate is 1.89%
1 hour+ late
5.5%
National rate is 8.3%
These figures cover 365 flights between September 2025 and August 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.
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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 146 of 365 flights, with 13:25 (60 flights) and 13:38 (59 flights) next.
- Departs 13:30146 flights40.0%
- Departs 13:2560 flights16.4%
- Departs 13:3859 flights16.2%
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 13:30 departure sits in the 11am–2pm window. Across every US flight scheduled in that window the on-time rate is 78.3%, and DL 1120 runs 5 points better at 83.0%. 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 1120 next to SEA to SLC
Every carrier on SEA to SLC combined arrived on time 83.4% of the time across 4,098 flights, so DL 1120 is about level with it. Delta flew 2,232 flights on the same city pair under all its flight numbers, including this one, and those ran 86.8% on time. Across its whole network Delta Air Lines managed 81.1%, which this flight beats by 2 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| DL 1120 | 365 | 83.0% | 64 min | 0.27% | B+ |
| All Delta Air Lines on SEA–SLC | 2,232 | 86.8% | 59 min | 0.49% | A+ |
| All carriers on SEA–SLC | 4,098 | 83.4% | 49 min | 0.78% | B+ |
| Delta Air Lines, whole network | 1,039,517 | 81.1% | 71 min | 1.74% | B |
Across the year
DL 1120 quarter by quarter
DL 1120 did not run the same all year. Its best quarter was Jul–Sep 2025 at 93.3% on time and its weakest Jul–Sep 2026 at 74.2%, a swing of 19 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 flights93.3%
- Oct–Dec 202592 flights82.6%
- Jan–Mar 202690 flights83.1%
- Apr–Jun 202691 flights85.7%
- Jul–Sep 202662 flights74.2%
Scale runs 65% to 100%.
By weekday, DL 1120 did best on Tuesday at 90.4% on time and worst on Thursday at 75.0%. Each day rests on about 52 flights, so a gap of 15 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late DL 1120 runs when it is late
DL 1120 often beats the schedule: 109 of 364 completed flights, 30%, arrived 15 minutes or more early. The 62 late arrivals split 21 under half an hour, 21 between 30 and 60 minutes, and 20 an hour or more.
- 15+ min early109 flights29.9%
- Within 15 min193 flights53.0%
- 15–29 min late21 flights5.8%
- 30–59 min late21 flights5.8%
- 1–2 hours late12 flights3.3%
- 2+ hours late8 flights2.2%
Scale runs 0% to 100%.
Share of 364 completed flights by arrival against schedule.
18 of 75 late departures made up the time and arrived on time, 24% of them. Only 5 left on time and still arrived late.
The worst days
Worst days for DL 1120
The latest arrival of the period was on 4 December 2025, 4 hours 46 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). The same cause led on three of the five worst days.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 4 December 2025 | 4 hours 46 minutes | Carrier |
| 26 December 2025 | 4 hours 27 minutes | Carrier |
| 15 October 2025 | 4 hours 10 minutes | Late-arriving aircraft |
| 16 July 2026 | 3 hours 26 minutes | Late-arriving aircraft |
| 15 January 2026 | 3 hours 15 minutes | Carrier |
Delay causes
Why DL 1120 runs late
Carrier accounts for 61% of the 3,963 delay minutes carriers reported here, and the remaining four split what is left.
- 61%Carrier
- 34%Late-arriving aircraft
- 5%National Airspace System
- 0%Extreme weather
The largest share of delay minutes, 61%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 2,411 of the 3,963 delay minutes reported here. The split is drawn from 3,963 delay minutes reported on DL 1120.
Cancellations are rare at 0.27%, 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
5.5% 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 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.
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 83.0% on time with 0.27% 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 1016 on the same route90.0%
- Delta Air Lines 1128 on the same route93.7%
- Delta Air Lines 1265 on the same route85.1%
- Delta Air Lines 1165 on the same route80.4%
- SkyWest Airlines 3298 on the same route79.3%
- Alaska Airlines 733 on the same route68.4%
- 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, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.