Flight number record
DL 847
Delta Air Lines · Salt Lake City to Washington
- Route
- SLC → IAD
- Departs
- 17:35
- Flights
- 364
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s DL 847, check with Delta Air Lines.
DL 847 lands a B, 3 points better than the national rate of 77.3%. About one flight in five arrives 15 minutes late or worse, and those flights are late by about an hour on average. That rests on 364 flights, with a median arrival 8 minutes early.
Key figures
On time
80.7%
Arrivals under 15 minutes late, of 358 completed flights
Avg delay
57 min
Across delayed arrivals only, not all flights
Cancelled
1.65%
National rate is 1.89%
1 hour+ late
6.1%
National rate is 8.3%
These figures cover 364 flights between September 2025 and August 2026. The median arrival is 8 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 847 flies
DL 847 flies SLC to IAD without a single fixed slot. Its most common scheduled departure was 17:35, used on 66 of 364 flights, with 17:55 (62 flights) and 17:50 (59 flights) next.
- Departs 17:3566 flights18.1%
- Departs 17:5562 flights17.0%
- Departs 17:5059 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 17:35 departure sits in the 5pm–8pm window. Across every US flight scheduled in that window the on-time rate is 68.0%, and DL 847 runs 13 points better at 80.7%. By that time of day most aircraft have flown several legs already, and whatever went wrong earlier is still in the schedule.
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Against the route
DL 847 next to SLC to IAD
Every carrier on SLC to IAD combined arrived on time 84.4% of the time across 702 flights, so DL 847 is 4 points behind it. Across its whole network Delta Air Lines managed 81.1%, close to this flight's figure.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| DL 847thin sample | 364 | 80.7% | 57 min | 1.65% | B |
| All Delta Air Lines on SLC–IADthin sample | 364 | 80.7% | 57 min | 1.65% | B |
| All carriers on SLC–IAD | 702 | 84.4% | 61 min | 1.71% | B |
| Delta Air Lines, whole network | 1,039,517 | 81.1% | 71 min | 1.74% | B |
Across the year
DL 847 quarter by quarter
DL 847 did not run the same all year. Its best quarter was Oct–Dec 2025 at 88.9% on time and its weakest Jul–Sep 2026 at 51.6%, a swing of 37 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 flights86.7%
- Oct–Dec 202591 flights88.9%
- Jan–Mar 202690 flights84.7%
- Apr–Jun 202691 flights86.8%
- Jul–Sep 202662 flights51.6%
Scale runs 45% to 95%.
By weekday, DL 847 did best on Tuesday at 92.2% on time and worst on Friday at 71.2%. Each day rests on about 52 flights, so a gap of 21 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late DL 847 runs when it is late
DL 847 often beats the schedule: 103 of 358 completed flights, 29%, arrived 15 minutes or more early. The 69 late arrivals split 24 under half an hour, 23 between 30 and 60 minutes, and 22 an hour or more.
- 15+ min early103 flights28.8%
- Within 15 min186 flights52.0%
- 15–29 min late24 flights6.7%
- 30–59 min late23 flights6.4%
- 1–2 hours late15 flights4.2%
- 2+ hours late7 flights2.0%
Scale runs 0% to 100%.
Share of 358 completed flights by arrival against schedule.
9 of 64 late departures made up the time and arrived on time, 14% of them. 14 flights left on time and still arrived late.
The worst days
Worst days for DL 847
The latest arrival of the period was on 18 September 2025, 3 hours 24 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 |
|---|---|---|
| 18 September 2025 | 3 hours 24 minutes | Carrier |
| 15 March 2026 | 3 hours 9 minutes | Carrier |
| 1 December 2025 | 2 hours 55 minutes | Late-arriving aircraft |
| 23 July 2026 | 2 hours 49 minutes | Carrier |
| 7 July 2026 | 2 hours 39 minutes | Carrier |
Delay causes
Why DL 847 runs late
Carrier accounts for 62% of the 3,905 delay minutes carriers reported here, and the remaining four split what is left.
- 62%Carrier
- 22%Late-arriving aircraft
- 13%National Airspace System
- 3%Extreme weather
The largest share of delay minutes, 62%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 2,414 of the 3,905 delay minutes reported here. The split is drawn from 3,905 delay minutes reported on DL 847.
Cancellations sit at 1.65% against a national 1.89%, which is ordinary. Diversions add another 0.00%.
Connections and routes
What a delay on this flight costs
6.1% 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.
At 1,827 miles this is transcontinental flying, and long routes get a quiet structural advantage. Scheduled block time on a flight this length carries more padding in absolute minutes, so a twenty-minute late departure often still becomes an on-time arrival. Read the on-time rate here as slightly flattering next to a short-haul route with the same operational quality.
Every one of the 364 flights under DL 847 in the data flew SLC to IAD. 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. 364 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 847
For a booking, read DL 847 as 80.7% on time with 1.65% cancelled over 364 flights. Those are rates from the past twelve months, not a forecast for any particular day.
Related
Where to go next
- Salt Lake City International (SLC) delay statistics
- Washington Dulles International (IAD) 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.