Flight number record
DL 1559
Delta Air Lines · Los Angeles to San Francisco
- Route
- LAX → SFO
- Departs
- 16:00
- Flights
- 347
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s DL 1559, check with Delta Air Lines.
DL 1559 draws a C+. About one flight in three arrives at least 15 minutes late, and the typical late arrival is about an hour behind schedule. Build slack into anything you connect to. That rests on 347 flights, with a median arrival 3 minutes late.
The national on-time rate over the same period is 77.3%, so DL 1559 runs 12 points behind the country as a whole. Across a thousand flights that is about 116 extra late arrivals.
Key figures
On time
65.7%
Arrivals under 15 minutes late, of 344 completed flights
Avg delay
55 min
Across delayed arrivals only, not all flights
Cancelled
0.86%
National rate is 1.89%
1 hour+ late
9.9%
National rate is 8.3%
These figures cover 347 flights between September 2025 and August 2026. Beyond the headline rate, 9.9% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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Schedule
When DL 1559 flies
DL 1559 flies LAX to SFO without a single fixed slot. Its most common scheduled departure was 16:00, used on 56 of 347 flights, with 16:20 (41 flights) and 16:30 (39 flights) next.
- Departs 16:0056 flights16.1%
- Departs 16:2041 flights11.8%
- Departs 16:3039 flights11.2%
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 16:00 departure sits in the 2pm–5pm window. Across every US flight scheduled in that window the on-time rate is 71.9%, and DL 1559 runs 6 points worse at 65.7%. 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 1559 next to LAX to SFO
Every carrier on LAX to SFO combined arrived on time 60.1% of the time across 11,437 flights, so DL 1559 is 6 points ahead of it. Delta flew 2,373 flights on the same city pair under all its flight numbers, including this one, and those ran 60.9% on time. Across its whole network Delta Air Lines managed 81.1%, which this flight trails by 15 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| DL 1559thin sample | 347 | 65.7% | 55 min | 0.86% | C+ |
| All Delta Air Lines on LAX–SFO | 2,373 | 60.9% | 53 min | 1.56% | D |
| All carriers on LAX–SFO | 11,437 | 60.1% | 57 min | 0.80% | D+ |
| Delta Air Lines, whole network | 1,039,517 | 81.1% | 71 min | 1.74% | B |
Across the year
DL 1559 quarter by quarter
DL 1559 did not run the same all year. Its best quarter was Jul–Sep 2025 at 83.3% on time and its weakest Jul–Sep 2026 at 51.7%, a swing of 32 points on roughly 69 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 202580 flights66.2%
- Jan–Mar 202686 flights81.2%
- Apr–Jun 202691 flights53.9%
- Jul–Sep 202660 flights51.7%
Scale runs 45% to 90%.
By weekday, DL 1559 did best on Wednesday at 72.0% on time and worst on Thursday at 56.0%. Each day rests on about 50 flights, so a gap of 16 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late DL 1559 runs when it is late
The 118 late arrivals split 35 under half an hour, 49 between 30 and 60 minutes, and 34 an hour or more.
- 15+ min early81 flights23.5%
- Within 15 min145 flights42.2%
- 15–29 min late35 flights10.2%
- 30–59 min late49 flights14.2%
- 1–2 hours late26 flights7.6%
- 2+ hours late8 flights2.3%
Scale runs 0% to 100%.
Share of 344 completed flights by arrival against schedule.
13 of 87 late departures made up the time and arrived on time, 15% of them. In the other direction, 44 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 1559
The latest arrival of the period was on 9 October 2025, 6 hours 27 minutes behind schedule; most of its delay minutes were filed as extreme weather. On four of the five worst days the largest share was filed as carrier-caused (crew, maintenance, fuelling, baggage).
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 9 October 2025 | 6 hours 27 minutes | Extreme weather |
| 5 July 2026 | 5 hours 5 minutes | Carrier |
| 30 March 2026 | 3 hours 35 minutes | Carrier |
| 12 February 2026 | 2 hours 59 minutes | Carrier |
| 21 October 2025 | 2 hours 42 minutes | Carrier |
Delay causes
Why DL 1559 runs late
Carriers report a reason for every delay minute they cause, in five DOT categories. The split below is by minutes, not by number of flights, so a handful of very long weather delays weighs as much as many short ones. It covers 6,538 reported delay minutes.
- 41%National Airspace System
- 31%Carrier
- 23%Late-arriving aircraft
- 6%Extreme weather
41% 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 2,674 minutes out of 6,538, against a national NAS share of 21%. The split is drawn from 6,538 delay minutes reported on DL 1559.
Cancellations are rare at 0.86%, 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
9.9% of arrivals land a full hour or more behind schedule, against 8.3% nationally. Ninety minutes is the honest minimum for a connection here, and two hours if the onward flight is on a separate ticket.
The same number turns up on three other city pairs in the data, including SFO to LAX (197), RSW to DTW (16) and DTW to RSW (16), but none flew often enough under DL 1559 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to LAX to SFO only.
One caution: this is a thin sample. 347 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 1559
For a booking, read DL 1559 as 65.7% on time with 0.86% cancelled over 347 flights. Those are rates from the past twelve months, not a forecast for any particular day.
Related
Where to go next
- LAX to SFO, every carrier and departure
- SFO to LAX, the return direction
- Delta Air Lines 2267 on the same route44.3%
- United Airlines 2019 on the same route65.1%
- Delta Air Lines 1421 on the same route94.1%
- United Airlines 1791 on the same route55.4%
- Delta Air Lines 1715 on the same route48.3%
- Delta Air Lines 2986 on the same route57.1%
- Los Angeles International (LAX) 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
- How often a connection fails at the major US hubs
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.