Flight number record
DL 2817
Delta Air Lines · Salt Lake City to Seattle
- Route
- SLC → SEA
- Departs
- 15:15
- Flights
- 363
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s DL 2817, check with Delta Air Lines.
DL 2817 lands a B+, level with the national rate of 77.3%. Roughly one flight in four arrives 15 minutes late or worse, and those flights are late by about 50 minutes on average. That rests on 363 flights, with a median arrival 5 minutes early.
Key figures
On time
77.3%
Arrivals under 15 minutes late, of 362 completed flights
Avg delay
50 min
Across delayed arrivals only, not all flights
Cancelled
0.28%
National rate is 1.89%
1 hour+ late
6.4%
National rate is 8.3%
These figures cover 363 flights between September 2025 and August 2026. The median arrival is 5 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 2817 flies
DL 2817 flies SLC to SEA without a single fixed slot. Its most common scheduled departure was 15:15, used on 57 of 363 flights, with 15:25 (56 flights) and 15:30 (55 flights) next.
- Departs 15:1557 flights15.7%
- Departs 15:2556 flights15.4%
- Departs 15:3055 flights15.2%
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 15:15 departure sits in the 2pm–5pm window. Across every US flight scheduled in that window the on-time rate is 71.9%, and DL 2817 runs 5 points better at 77.3%. 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 2817 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 2817 is 3 points behind 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 trails by 4 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| DL 2817thin sample | 363 | 77.3% | 50 min | 0.28% | 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 2817 quarter by quarter
DL 2817 did not run the same all year. Its best quarter was Jan–Mar 2026 at 86.5% on time and its weakest Jul–Sep 2025 at 60.0%, a swing of 27 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 flights60.0%
- Oct–Dec 202590 flights70.0%
- Jan–Mar 202690 flights86.5%
- Apr–Jun 202691 flights76.9%
- Jul–Sep 202662 flights83.9%
Scale runs 50% to 90%.
By weekday, DL 2817 did best on Saturday at 88.5% on time and worst on Friday at 66.0%. Each day rests on about 52 flights, so a gap of 23 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late DL 2817 runs when it is late
DL 2817 often beats the schedule: 106 of 362 completed flights, 29%, arrived 15 minutes or more early. The 82 late arrivals split 34 under half an hour, 25 between 30 and 60 minutes, and 23 an hour or more.
- 15+ min early106 flights29.3%
- Within 15 min174 flights48.1%
- 15–29 min late34 flights9.4%
- 30–59 min late25 flights6.9%
- 1–2 hours late16 flights4.4%
- 2+ hours late7 flights1.9%
Scale runs 0% to 100%.
Share of 362 completed flights by arrival against schedule.
14 of 70 late departures made up the time and arrived on time, 20% of them. In the other direction, 26 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 2817
The latest arrival of the period was on 19 July 2026, 3 hours 25 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). The five worst days are spread across July, May, September, February and October, with no single month standing out.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 19 July 2026 | 3 hours 25 minutes | Carrier |
| 27 May 2026 | 2 hours 32 minutes | Extreme weather |
| 1 September 2025 | 2 hours 29 minutes | Carrier |
| 18 February 2026 | 2 hours 28 minutes | Late-arriving aircraft |
| 20 October 2025 | 2 hours 27 minutes | Late-arriving aircraft |
Delay causes
Why DL 2817 runs late
Carrier accounts for 47% of the 4,095 delay minutes carriers reported here, and the remaining four split what is left.
- 47%Carrier
- 26%Late-arriving aircraft
- 21%National Airspace System
- 6%Extreme weather
The largest share of delay minutes, 47%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 1,923 of the 4,095 delay minutes reported here. The split is drawn from 4,095 delay minutes reported on DL 2817.
Cancellations are rare at 0.28%, 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
6.4% 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 50 minutes, 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 363 flights under DL 2817 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. 363 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 2817
For a booking, read DL 2817 as 77.3% on time with 0.28% cancelled over 363 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 871 on the same route80.3%
- Alaska Airlines 796 on the same route83.9%
- Delta Air Lines 2921 on the same route84.0%
- 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.