Flight number record

DL 1559

Delta Air Lines · Los Angeles to San Francisco

Route: LAX → SFO
Departs: 16:00
Flights: 348
Period: July 2025 to June 2026

Historical statistics for July 2025 to June 2026, not live status. For today’s DL 1559, check with Delta Air Lines.

DL 1559 sits in the middle of the pack with a C+. About seven flights in ten arrive on time by the DOT's definition, 7 points worse than the national rate of 77.6%. The late ones land about an hour behind schedule. That rests on 348 flights, with a median arrival 2 minutes early.

The national on-time rate over the same period is 77.6%, so DL 1559 runs 7 points behind the country as a whole. Across a thousand flights that is about 69 extra late arrivals.

On time

70.7%

Arrivals under 15 minutes late, of 345 completed flights

Avg delay

55 min

Across delayed arrivals only, not all flights

Cancelled

0.86%

National rate is 1.81%

1 hour+ late

8.1%

National rate is 8.1%

These figures cover 348 flights between July 2025 and June 2026. Beyond the headline rate, 8.1% of arrivals land a full hour or more behind schedule. That is the number that wrecks a connection, and it is not visible in an on-time percentage alone.

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 77 of 348 flights, with 16:25 (67 flights) and 16:20 (41 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.

Departs 16:0077 flights22.1%
Departs 16:2567 flights19.3%
Departs 16:2041 flights11.8%

Scale runs 0% to 100%. Rows with fewer than 30 flights show a dash.

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 72.4%, and DL 1559 runs level with that at 70.7%. Midday slots inherit some of the morning's delays without yet carrying the full weight of the evening's.

Against the route

DL 1559 next to LAX to SFO

Every carrier on LAX to SFO combined arrived on time 64.8% of the time across 11,013 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 65.2% on time. Across its whole network Delta Air Lines managed 81.6%, which this flight trails by 11 points.

DL 1559 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
DL 1559thin sample	348	70.7%	55 min	0.86%	C+
All Delta Air Lines on LAX–SFO	2,373	65.2%	55 min	1.52%	C
All carriers on LAX–SFO	11,013	64.8%	59 min	0.83%	D+
Delta Air Lines, whole network	1,038,570	81.6%	71 min	1.62%	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 81.3% on time and its weakest Apr–Jun 2026 at 53.9%, a swing of 27 points on roughly 87 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 202591 flights81.3%
Oct–Dec 202580 flights66.2%
Jan–Mar 202686 flights81.2%
Apr–Jun 202691 flights53.9%

Scale runs 45% to 85%. Rows with fewer than 30 flights show a dash.

By weekday, DL 1559 ranged from 66.0% on Thursday to 76.0% on Wednesday. With about 50 flights behind each day, a spread of 10 points is inside normal variation, so the day you fly is not worth changing for this flight.

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 5,562 reported delay minutes.

Carrier
38%
National Airspace System
32%
Late-arriving aircraft
23%
Extreme weather
7%

The largest share of delay minutes, 38%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. Unlike weather, that is a management outcome, and it is the category where the gap between two carriers on the same schedule is genuinely earned. It accounts for 2,110 of the 5,562 delay minutes reported here. The split is drawn from 5,562 delay minutes reported on DL 1559.

Cancellations are rare at 0.86%, below the national 1.81% 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

8.1% of arrivals land an hour or more late, close to the national 8.1%. That is the figure that decides a connection, and it says 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.

The same number turns up on three other city pairs in the data, including SFO to LAX (193), 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. 348 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 70.7% on time with 0.86% cancelled over 348 flights. Those are rates from the past twelve months, not a forecast for any particular day.

Where to go next

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, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.

Key figures