Flight number record
DL 823
Delta Air Lines · Atlanta to San Francisco
- Route
- ATL → SFO
- Departs
- 15:35
- Flights
- 349
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s DL 823, check with Delta Air Lines.
DL 823 draws a D. About one flight in three arrives at least 15 minutes late, and the typical late arrival is about 50 minutes behind schedule. Build slack into anything you connect to. That rests on 349 flights, with a median arrival 4 minutes late.
The national on-time rate over the same period is 77.3%, so DL 823 runs 13 points behind the country as a whole. Across a thousand flights that is about 125 extra late arrivals.
Key figures
On time
64.8%
Arrivals under 15 minutes late, of 344 completed flights
Avg delay
51 min
Across delayed arrivals only, not all flights
Cancelled
1.15%
National rate is 1.89%
1 hour+ late
8.1%
National rate is 8.3%
These figures cover 349 flights between September 2025 and August 2026. Beyond the headline rate, 8.1% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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Schedule
When DL 823 flies
DL 823 flies ATL to SFO without a single fixed slot. Its most common scheduled departure was 15:35, used on 85 of 349 flights, with 15:20 (58 flights) and 15:59 (45 flights) next.
- Departs 15:3585 flights24.4%
- Departs 15:2058 flights16.6%
- Departs 15:5945 flights12.9%
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 15:35 departure sits in the 2pm–5pm window. Across every US flight scheduled in that window the on-time rate is 71.9%, and DL 823 runs 7 points worse at 64.8%. 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 823 next to ATL to SFO
Every carrier on ATL to SFO combined arrived on time 69.9% of the time across 3,339 flights, so DL 823 is 5 points behind it. Delta flew 2,393 flights on the same city pair under all its flight numbers, including this one, and those ran 68.5% on time. Across its whole network Delta Air Lines managed 81.1%, which this flight trails by 16 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| DL 823thin sample | 349 | 64.8% | 51 min | 1.15% | D |
| All Delta Air Lines on ATL–SFO | 2,393 | 68.5% | 55 min | 0.67% | C+ |
| All carriers on ATL–SFO | 3,339 | 69.9% | 58 min | 0.69% | C+ |
| Delta Air Lines, whole network | 1,039,517 | 81.1% | 71 min | 1.74% | B |
Across the year
DL 823 quarter by quarter
DL 823 did not run the same all year. Its best quarter was Jan–Mar 2026 at 70.9% on time and its weakest Apr–Jun 2026 at 57.8%, a swing of 13 points on roughly 70 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 flights63.3%
- Oct–Dec 202591 flights70.0%
- Jan–Mar 202688 flights70.9%
- Apr–Jun 202691 flights57.8%
- Jul–Sep 202649 flights58.3%
Scale runs 50% to 75%.
By weekday, DL 823 did best on Tuesday at 75.0% on time and worst on Sunday at 57.1%. Each day rests on about 50 flights, so a gap of 18 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late DL 823 runs when it is late
Most of the lateness is short. 61 of the 121 late arrivals were under half an hour behind, and 28 reached an hour or more.
- 15+ min early46 flights13.4%
- Within 15 min177 flights51.5%
- 15–29 min late61 flights17.7%
- 30–59 min late32 flights9.3%
- 1–2 hours late14 flights4.1%
- 2+ hours late14 flights4.1%
Scale runs 0% to 100%.
Share of 344 completed flights by arrival against schedule.
Time lost at the gate mostly stays lost. Of 76 departures that left 15 minutes late or more, only 9 made it up before arrival. In the other direction, 54 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 823
The latest arrival of the period was on 8 December 2025, 5 hours 54 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). The same cause led on three of the five worst days.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 8 December 2025 | 5 hours 54 minutes | Carrier |
| 1 February 2026 | 3 hours 24 minutes | Carrier |
| 18 June 2026 | 3 hours 3 minutes | Extreme weather |
| 20 April 2026 | 3 hours | National Airspace System |
| 8 January 2026 | 2 hours 43 minutes | Carrier |
Delay causes
Why DL 823 runs late
Carrier accounts for 45% of the 6,117 delay minutes carriers reported here, and the remaining four split what is left.
- 45%Carrier
- 43%National Airspace System
- 9%Late-arriving aircraft
- 4%Extreme weather
43% 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 2,636 minutes out of 6,117, against a national NAS share of 21%. The split is drawn from 6,117 delay minutes reported on DL 823.
Cancellations sit at 1.15% against a national 1.89%, which is ordinary. Diversions add another 0.29%.
Connections and routes
What a delay on this flight costs
8.1% of arrivals land an hour or more late, close to the national 8.3%, 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 50 minutes, which a normal layover absorbs.
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.
Every one of the 349 flights under DL 823 in the data flew ATL to SFO. 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. 349 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 823
For a booking, DL 823 is one of the weaker ways to fly ATL to SFO: 5 points below the route as a whole. If the schedule allows, compare it with the other departures listed on the route page before settling on this one.
Related
Where to go next
- ATL to SFO, every carrier and departure
- SFO to ATL, the return direction
- Delta Air Lines 517 on the same route65.4%
- Delta Air Lines 693 on the same route81.2%
- Delta Air Lines 656 on the same route71.8%
- Hartsfield-Jackson Atlanta International (ATL) 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
- Connecting flights: how much buffer the data says you need
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.