Flight number record
DL 2921
Delta Air Lines · Salt Lake City to Seattle
- Route
- SLC → SEA
- Departs
- 13:20
- Flights
- 289
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s DL 2921, check with Delta Air Lines.
DL 2921 earns a B+. More than four flights in five arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 7 points better than the national rate of 77.3%. When something does go wrong the average delay runs about 50 minutes. That rests on 289 flights, with a median arrival 7 minutes early.
Set against the rest of the country, DL 2921's record is 7 points better than the US average of 77.3%. That gap is worth roughly 67 fewer late arrivals for every thousand flights.
Key figures
On time
84.0%
Arrivals under 15 minutes late, of 287 completed flights
Avg delay
49 min
Across delayed arrivals only, not all flights
Cancelled
0.69%
National rate is 1.89%
1 hour+ late
2.4%
National rate is 8.3%
These figures cover 289 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 2921 flies
DL 2921 flies SLC to SEA without a single fixed slot. Its most common scheduled departure was 13:20, used on 78 of 289 flights, with 13:40 (72 flights) and 13:25 (33 flights) next.
- Departs 13:2078 flights27.0%
- Departs 13:4072 flights24.9%
- Departs 13:2533 flights11.4%
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 13:20 departure sits in the 11am–2pm window. Across every US flight scheduled in that window the on-time rate is 78.3%, and DL 2921 runs 6 points better at 84.0%. 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 2921 next to SLC to SEA
Every carrier on SLC to SEA combined arrived on time 79.9% of the time across 4,098 flights, so DL 2921 is 4 points ahead of it. Delta flew 2,234 flights on the same city pair under all its flight numbers, including this one, and those ran 82.7% on time. Across its whole network Delta Air Lines managed 81.1%, which this flight beats by 3 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| DL 2921thin sample | 289 | 84.0% | 49 min | 0.69% | B+ |
| All Delta Air Lines on SLC–SEA | 2,234 | 82.7% | 53 min | 0.49% | B+ |
| All carriers on SLC–SEA | 4,098 | 79.9% | 55 min | 0.81% | B+ |
| Delta Air Lines, whole network | 1,039,517 | 81.1% | 71 min | 1.74% | B |
Across the year
DL 2921 quarter by quarter
DL 2921 did not run the same all year. Its best quarter was Jul–Sep 2025 at 93.3% on time and its weakest Oct–Dec 2025 at 74.0%, a swing of 19 points on roughly 72 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 202578 flights74.0%
- Jan–Mar 202628 flights—
- Apr–Jun 202691 flights89.0%
- Jul–Sep 202662 flights80.6%
Scale runs 65% to 100%. Rows with fewer than 30 flights show a dash.
By weekday, DL 2921 did best on Saturday at 92.9% on time and worst on Friday at 71.8%. Each day rests on about 41 flights, so a gap of 21 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late DL 2921 runs when it is late
DL 2921 often beats the schedule: 72 of 287 completed flights, 25%, arrived 15 minutes or more early. The 46 late arrivals split 19 under half an hour, 20 between 30 and 60 minutes, and 7 an hour or more.
- 15+ min early72 flights25.1%
- Within 15 min169 flights58.9%
- 15–29 min late19 flights6.6%
- 30–59 min late20 flights7.0%
- 1–2 hours late3 flights1.0%
- 2+ hours late4 flights1.4%
Scale runs 0% to 100%.
Share of 287 completed flights by arrival against schedule.
5 of 36 late departures made up the time and arrived on time, 14% of them. In the other direction, 15 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 SEA.
The worst days
Worst days for DL 2921
The latest arrival of the period was on 30 October 2025, 3 hours 59 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). The same cause led on four of the five worst days.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 30 October 2025 | 3 hours 59 minutes | Carrier |
| 12 September 2025 | 3 hours 33 minutes | Carrier |
| 4 November 2025 | 3 hours 7 minutes | Carrier |
| 5 December 2025 | 2 hours 19 minutes | Carrier |
| 22 May 2026 | 1 hour 40 minutes | Late-arriving aircraft |
Delay causes
Why DL 2921 runs late
Carrier accounts for 51% of the 2,255 delay minutes carriers reported here, and the remaining four split what is left.
- 51%Carrier
- 26%Late-arriving aircraft
- 22%National Airspace System
The largest share of delay minutes, 51%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 1,156 of the 2,255 delay minutes reported here. The split is drawn from 2,255 delay minutes reported on DL 2921.
Cancellations are rare at 0.69%, 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 2.4% 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 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 289 flights under DL 2921 in the data flew SLC to SEA. 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. 289 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 2921
For a booking, read DL 2921 as 84.0% on time with 0.69% cancelled over 289 flights. Those are rates from the past twelve months, not a forecast for any particular day.
Related
Where to go next
- SLC to SEA, every carrier and departure
- SEA to SLC, the return direction
- Delta Air Lines 2874 on the same route92.6%
- Delta Air Lines 2995 on the same route87.1%
- Delta Air Lines 2817 on the same route77.3%
- Delta Air Lines 871 on the same route80.3%
- Alaska Airlines 796 on the same route83.9%
- Alaska Airlines 734 on the same route65.9%
- Salt Lake City International (SLC) delay statistics
- Seattle-Tacoma International (SEA) 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
- Worst months to fly in the US, ranked by the data
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.