Flight number record

DL 517

Delta Air Lines · Atlanta to San Francisco

Route: ATL → SFO
Departs: 16:53
Flights: 302
Period: July 2025 to June 2026

Historical statistics for July 2025 to June 2026, not live status. For today’s DL 517, check with Delta Air Lines.

DL 517 sits in the middle of the pack with a C+. About seven flights in ten arrive on time by the DOT's definition, 9 points worse than the national rate of 77.6%. The late ones land about an hour behind schedule. That rests on 302 flights, with a median arrival 3 minutes late.

The national on-time rate over the same period is 77.6%, so DL 517 runs 9 points behind the country as a whole. Across a thousand flights that is about 88 extra late arrivals.

On time

68.8%

Arrivals under 15 minutes late, of 301 completed flights

Avg delay

58 min

Across delayed arrivals only, not all flights

Cancelled

0.33%

National rate is 1.81%

1 hour+ late

9.3%

National rate is 8.1%

These figures cover 302 flights between July 2025 and June 2026. Beyond the headline rate, 9.3% 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 517 flies

DL 517 flies ATL to SFO without a single fixed slot. Its most common scheduled departure was 16:53, used on 56 of 302 flights, with 16:59 (56 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.

Departs 16:5356 flights18.5%
Departs 16:5956 flights18.5%

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 16:53 departure sits in the 2pm–5pm window. Across every US flight scheduled in that window the on-time rate is 72.4%, and DL 517 runs 4 points worse at 68.8%. Midday slots inherit some of the morning's delays without yet carrying the full weight of the evening's.

Against the route

DL 517 next to ATL to SFO

Every carrier on ATL to SFO combined arrived on time 71.4% of the time across 3,354 flights, so DL 517 is 3 points behind it. Delta flew 2,410 flights on the same city pair under all its flight numbers, including this one, and those ran 70.2% on time. Across its whole network Delta Air Lines managed 81.6%, which this flight trails by 13 points.

DL 517 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
DL 517thin sample	302	68.8%	58 min	0.33%	C+
All Delta Air Lines on ATL–SFO	2,410	70.2%	55 min	0.62%	C+
All carriers on ATL–SFO	3,354	71.4%	58 min	0.63%	C+
Delta Air Lines, whole network	1,038,570	81.6%	71 min	1.62%	B

Across the year

DL 517 quarter by quarter

DL 517 did not run the same all year. Its best quarter was Jan–Mar 2026 at 83.5% on time and its weakest Apr–Jun 2026 at 59.3%, a swing of 24 points on roughly 76 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 202592 flights67.4%
Oct–Dec 202533 flights60.6%
Jan–Mar 202686 flights83.5%
Apr–Jun 202691 flights59.3%

Scale runs 50% to 90%. Rows with fewer than 30 flights show a dash.

By weekday, DL 517 did best on Tuesday at 77.8% on time and worst on Sunday at 55.8%. Each day rests on about 43 flights, so a gap of 22 points is worth noticing but could still narrow in another year.

Delay causes

Why DL 517 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 5,456 reported delay minutes.

National Airspace System
41%
Carrier
39%
Extreme weather
12%
Late-arriving aircraft
9%

Extreme weather accounts for 12% of delay minutes, well above the single-digit share typical across the system. Weather delays are lumpy: they arrive as whole bad days rather than as a steady drag, so the quarterly figures above are the more useful view of the risk. The national share is 6%, so this operation carries roughly 1.8 times the usual weather exposure. The split is drawn from 5,456 delay minutes reported on DL 517.

Cancellations are rare at 0.33%, 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

For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 9.3% of arrivals land a full hour or more behind schedule, against 8.1% nationally. A 45-minute layover does not survive that, and no amount of walking quickly changes it. Ninety minutes is the honest minimum here, and two hours if the onward flight is on a separate ticket.

At 2,139 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.

The same number turns up on three other city pairs in the data, including DFW to ATL (18), LAX to BNA (16) and SFO to ATL (12), but none flew often enough under DL 517 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to ATL to SFO only.

One caution: this is a thin sample. 302 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 517

For a booking, read DL 517 as 68.8% on time with 0.33% cancelled over 302 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