Flight number record
DL 671
Delta Air Lines · Salt Lake City to New York
- Route
- SLC → JFK
- Departs
- 14:35
- Flights
- 363
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s DL 671, check with Delta Air Lines.
DL 671 lands a B, 2 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 363 flights, with a median arrival 16 minutes early.
Key figures
On time
79.0%
Arrivals under 15 minutes late, of 347 completed flights
Avg delay
64 min
Across delayed arrivals only, not all flights
Cancelled
2.48%
National rate is 1.89%
1 hour+ late
8.9%
National rate is 8.3%
These figures cover 363 flights between September 2025 and August 2026. Beyond the headline rate, 8.9% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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Schedule
When DL 671 flies
DL 671 flies SLC to JFK without a single fixed slot. Its most common scheduled departure was 14:35, used on 77 of 363 flights, with 13:37 (38 flights) next.
- Departs 14:3577 flights21.2%
- Departs 13:3738 flights10.5%
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 14:35 departure sits in the 2pm–5pm window. Across every US flight scheduled in that window the on-time rate is 71.9%, and DL 671 runs 7 points better at 79.0%. 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 671 next to SLC to JFK
Every carrier on SLC to JFK combined arrived on time 81.3% of the time across 1,932 flights, so DL 671 is 2 points behind it. Delta flew 1,539 flights on the same city pair under all its flight numbers, including this one, and those ran 83.2% on time. Across its whole network Delta Air Lines managed 81.1%, which this flight trails by 2 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| DL 671thin sample | 363 | 79.0% | 64 min | 2.48% | B |
| All Delta Air Lines on SLC–JFK | 1,539 | 83.2% | 66 min | 1.95% | B |
| All carriers on SLC–JFK | 1,932 | 81.3% | 72 min | 2.59% | B |
| Delta Air Lines, whole network | 1,039,517 | 81.1% | 71 min | 1.74% | B |
Across the year
DL 671 quarter by quarter
DL 671 did not run the same all year. Its best quarter was Jul–Sep 2025 at 90.0% on time and its weakest Jul–Sep 2026 at 72.2%, a swing of 18 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 flights90.0%
- Oct–Dec 202590 flights75.0%
- Jan–Mar 202690 flights81.4%
- Apr–Jun 202691 flights80.9%
- Jul–Sep 202662 flights72.2%
Scale runs 65% to 95%.
By weekday, DL 671 did best on Friday at 85.7% on time and worst on Thursday at 67.3%. Each day rests on about 52 flights, so a gap of 18 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late DL 671 runs when it is late
DL 671 often beats the schedule: 183 of 347 completed flights, 53%, arrived 15 minutes or more early. The 73 late arrivals split 23 under half an hour, 19 between 30 and 60 minutes, and 31 an hour or more.
- 15+ min early183 flights52.7%
- Within 15 min91 flights26.2%
- 15–29 min late23 flights6.6%
- 30–59 min late19 flights5.5%
- 1–2 hours late23 flights6.6%
- 2+ hours late8 flights2.3%
Scale runs 0% to 100%.
Share of 347 completed flights by arrival against schedule.
24 of 83 late departures made up the time and arrived on time, 29% of them. 14 flights left on time and still arrived late.
The worst days
Worst days for DL 671
The latest arrival of the period was on 7 August 2026, 5 hours 47 minutes behind schedule; most of its delay minutes were filed as national airspace system delay. The five worst days are spread across August, July, October, February and December, with no single month standing out.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 7 August 2026 | 5 hours 47 minutes | National Airspace System |
| 8 July 2026 | 4 hours 2 minutes | Carrier |
| 30 October 2025 | 3 hours 31 minutes | Extreme weather |
| 18 February 2026 | 3 hours 25 minutes | Extreme weather |
| 14 December 2025 | 2 hours 23 minutes | Late-arriving aircraft |
Delay causes
Why DL 671 runs late
National Airspace System accounts for 50% of the 4,664 delay minutes carriers reported here, and the remaining four split what is left.
- 50%National Airspace System
- 25%Carrier
- 17%Late-arriving aircraft
- 9%Extreme weather
50% of delay minutes are charged to the National Airspace System: air traffic volume, runway configuration, ground stops. No carrier can price its way out of that, which is why airport choice moves the number here more than carrier choice does. That is 2,347 minutes out of 4,664, against a national NAS share of 21%. The split is drawn from 4,664 delay minutes reported on DL 671.
Cancellations sit at 2.48% against a national 1.89%, which is ordinary. Diversions add another 1.93%.
Connections and routes
What a delay on this flight costs
8.9% 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 1,990 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 363 flights under DL 671 in the data flew SLC to JFK. 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 671
For a booking, read DL 671 as 79.0% on time with 2.48% 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 JFK, every carrier and departure
- JFK to SLC, the return direction
- Delta Air Lines 697 on the same route80.3%
- Delta Air Lines 705 on the same route86.5%
- Salt Lake City International (SLC) delay statistics
- John F. Kennedy International (JFK) 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.