Flight number record
DL 668
Delta Air Lines · New York to San Francisco
- Route
- JFK → SFO
- Departs
- 07:00
- Flights
- 359
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s DL 668, check with Delta Air Lines.
DL 668 sits in the middle of the pack with a C. About seven flights in ten arrive on time by the DOT's definition, 6 points worse than the national rate of 77.3%. The late ones land about an hour behind schedule. That rests on 359 flights, with a median arrival 5 minutes early.
The national on-time rate over the same period is 77.3%, so DL 668 runs 6 points behind the country as a whole. Across a thousand flights that is about 55 extra late arrivals.
Key figures
On time
71.8%
Arrivals under 15 minutes late, of 351 completed flights
Avg delay
62 min
Across delayed arrivals only, not all flights
Cancelled
1.95%
National rate is 1.89%
1 hour+ late
7.7%
National rate is 8.3%
These figures cover 359 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 668 flies
DL 668 flies JFK to SFO without a single fixed slot. Its most common scheduled departure was 07:00, used on 279 of 359 flights.
- Departs 07:00279 flights77.7%
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 07:00 departure sits in the 5am–8am window. Across every US flight scheduled in that window the on-time rate is 89.3%, and DL 668 runs 18 points worse at 71.8%. Early departures usually start with an aircraft that has not flown yet that day, which is most of why the window does well.
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Against the route
DL 668 next to JFK to SFO
Every carrier on JFK to SFO combined arrived on time 71.4% of the time across 6,800 flights, so DL 668 is about level with it. Delta flew 2,231 flights on the same city pair under all its flight numbers, including this one, and those ran 67.3% on time. Across its whole network Delta Air Lines managed 81.1%, which this flight trails by 9 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| DL 668thin sample | 359 | 71.8% | 62 min | 1.95% | C |
| All Delta Air Lines on JFK–SFO | 2,231 | 67.3% | 70 min | 2.20% | C |
| All carriers on JFK–SFO | 6,800 | 71.4% | 69 min | 2.57% | C |
| Delta Air Lines, whole network | 1,039,517 | 81.1% | 71 min | 1.74% | B |
Across the year
DL 668 quarter by quarter
DL 668 did not run the same all year. Its best quarter was Jul–Sep 2025 at 83.3% on time and its weakest Apr–Jun 2026 at 64.4%, 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 flights83.3%
- Oct–Dec 202589 flights67.0%
- Jan–Mar 202689 flights74.1%
- Apr–Jun 202689 flights64.4%
- Jul–Sep 202662 flights80.3%
Scale runs 55% to 90%.
By weekday, DL 668 did best on Wednesday at 80.8% on time and worst on Monday at 66.0%. Each day rests on about 51 flights, so a gap of 15 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late DL 668 runs when it is late
DL 668 often beats the schedule: 113 of 351 completed flights, 32%, arrived 15 minutes or more early. The 99 late arrivals split 48 under half an hour, 24 between 30 and 60 minutes, and 27 an hour or more.
- 15+ min early113 flights32.2%
- Within 15 min139 flights39.6%
- 15–29 min late48 flights13.7%
- 30–59 min late24 flights6.8%
- 1–2 hours late16 flights4.6%
- 2+ hours late11 flights3.1%
Scale runs 0% to 100%.
Share of 351 completed flights by arrival against schedule.
7 of 37 late departures made up the time and arrived on time, 19% of them. In the other direction, 69 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 SFO.
The worst days
Worst days for DL 668
The latest arrival of the period was on 7 November 2025, 11 hours 31 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). The same cause led on five of the five worst days.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 7 November 2025 | 11 hours 31 minutes | Carrier |
| 3 April 2026 | 10 hours 12 minutes | Carrier |
| 2 August 2026 | 5 hours | Carrier |
| 6 April 2026 | 4 hours 17 minutes | Carrier |
| 8 August 2026 | 3 hours 55 minutes | Carrier |
Delay causes
Why DL 668 runs late
Carrier accounts for 53% of the 6,155 delay minutes carriers reported here, and the remaining four split what is left.
- 53%Carrier
- 41%National Airspace System
- 5%Late-arriving aircraft
- 1%Extreme weather
The largest share of delay minutes, 53%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 3,243 of the 6,155 delay minutes reported here. The split is drawn from 6,155 delay minutes reported on DL 668.
Cancellations sit at 1.95% against a national 1.89%, which is ordinary. Diversions add another 0.28%.
Connections and routes
What a delay on this flight costs
7.7% 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 2,586 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.
DL 668 is not only a JFK to SFO flight. It also flew SFO to JFK (346 flights, 73.1% on time) often enough to be scored on its own. Airlines attach one number to several legs of an aircraft's day, and each leg keeps its own record here, so check which city pair is on your booking before reading a rate.
One caution: this is a thin sample. 359 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.
| Also flown as | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| SFO to JFKthin sample | 346 | 73.1% | 89 min | 2.60% | C |
What to do with this
Booking DL 668
For a booking, read DL 668 as 71.8% on time with 1.95% cancelled over 359 flights. Those are rates from the past twelve months, not a forecast for any particular day.
Related
Where to go next
- JFK to SFO, every carrier and departure
- SFO to JFK, the return direction
- American Airlines 179 on the same route79.8%
- American Airlines 177 on the same route60.4%
- Delta Air Lines 667 on the same route55.7%
- American Airlines 15 on the same route73.7%
- JetBlue Airways 115 on the same route80.9%
- Delta Air Lines 679 on the same route72.7%
- John F. Kennedy International (JFK) delay statistics
- San Francisco International (SFO) 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.