Carrier performance at one airport
DL→SFO
Delta Air Lines at San Francisco International
- Departures
- 13,973
- Period
- September 2025 to August 2026
- Routes
- 9
- Rank here
- #3 of 8
Delta Air Lines at San Francisco sits in the middle of the pack with a B. Close to three flights in four arrive on time by the DOT's definition, 2 points worse than the national rate of 77.3%. The late ones land about an hour behind schedule. That rests on 13,973 flights, of which United Airlines flew 62,048 at 79.8% on time.
Measured against the airport rather than the country, Delta Air Lines runs half a point ahead of the 75.3% weighted average across all carriers at SFO. That is the comparison worth making: every operator here works the same runways, the same airspace and the same weather.
Key figures
On time
75.8%
13,762 completed departures
Avg delay
67 min
Across delayed flights only
Cancelled
1.29%
At SFO, this carrier only
Rank here
#3
Of 8 carriers clearing the floor at SFO
These figures cover 14,000 flights between September 2025 and August 2026. The median arrival is 6 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.
Against the competition
Every carrier at SFO, ranked
The choice of carrier is not cosmetic here. United Airlines arrives on time 79.8% of the time; Southwest Airlines manages 54.8%. Sample sizes sit next to every figure, because a two-point gap across 9,968 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| United Airlines | 62,048 | 79.8% | 58 min | 0.46% | B+ |
| American Airlines | 11,939 | 76.4% | 102 min | 1.84% | B |
| Delta Air Lines (this page) | 13,973 | 75.8% | 67 min | 1.29% | B |
| JetBlue Airways | 4,519 | 75.6% | 76 min | 2.21% | B |
| Alaska Airlines | 10,629 | 75.0% | 55 min | 1.10% | B |
| SkyWest Airlines | 31,536 | 73.8% | 74 min | 1.31% | C |
| Frontier Airlines | 3,581 | 62.7% | 81 min | 2.18% | D |
| Southwest Airlines | 9,968 | 54.8% | 61 min | 0.90% | F+ |
The spread between United and Southwest is 25 points, wide enough that it should decide the booking. On a hundred trips that is 25 more arrivals inside the on-time window.
Route by route
Where Delta Air Lines flies from SFO
Delta Air Lines operates 9 routes out of SFO with enough volume to report. Route records inside one carrier at one airport still spread widely, because a short shuttle and a transcontinental have very different exposure to a late inbound.
| Route | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| SFO to ATL · Atlanta | 2,390 | 81.1% | 70 min | 0.71% | B+ |
| SFO to LAX · Los Angeles | 2,373 | 69.8% | 63 min | 1.56% | C |
| SFO to JFK · New York | 2,230 | 77.2% | 71 min | 2.15% | B |
| SFO to SLC · Salt Lake City | 1,714 | 75.7% | 74 min | 0.93% | B+ |
| SFO to MSP · Minneapolis | 1,449 | 79.6% | 60 min | 0.83% | B+ |
| SFO to DTW · Detroit | 1,385 | 75.4% | 53 min | 0.79% | B+ |
| SFO to SEA · Seattle | 986 | 79.5% | 70 min | 1.83% | B |
| SFO to BOS · Boston | 946 | 71.5% | 69 min | 1.59% | C |
| SFO to AUS · Austin | 500 | 64.8% | 86 min | 1.20% | D |
Flight by flight
Delta Air Lines flight numbers from SFO
15 Delta Air Lines flight numbers leaving SFO flew their main route often enough to have a record of their own. Grouped by destination.
- DL 570to ATL 06:0091.4%
- DL 640to ATL 08:0089.5%
- DL 400to BOS 07:1088.5%
- DL 335to DTW 22:5571.5%
- DL 772to DTW 05:5093.7%
- DL 383to JFK 09:0087.1%
- DL 405to JFK 07:0088.8%
- DL 1421to LAX 08:5589.7%
- DL 1598to LAX 06:0093.4%
- DL 1715to LAX 10:4056.1%
- DL 2159to MSP 15:2672.7%
- DL 2178to MSP 06:0094.4%
- DL 2721to SEA 05:5595.3%
- DL 920to SLC 09:5576.1%
- DL 1331to SLC 06:0096.1%
Departure window
Best time of day for this operation
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 26 points, against 25 points between the best and worst carrier.
- 5am–8am3,027 flights92.8%
- 8am–11am1,900 flights80.4%
- 11am–2pm3,279 flights68.0%
- 2pm–5pm2,151 flights66.7%
- 5pm–8pm1,301 flights67.2%
- 8pm–5am2,315 flights74.3%
Scale runs 60% to 100%.
Book the early departure. Flights leaving between 5am–8am arrive on time 92.8% of the time, against 66.7% for the afternoon window. That is 26 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 11am–2pm window is the busiest, with 3,279 flights scheduled in it.
Across the year
Seasonal pattern
July is the worst month at 62.3% on time, 26 points below March, the best at 87.8%. Summer afternoon convection and peak-season schedules land on the same weeks every year, so this is a pattern you can book around rather than a run of bad luck. July was the busiest month here, with 1,318 flights.
Delay causes
What holds this operation up
- 51%Late-arriving aircraft
- 30%Carrier
- 17%National Airspace System
- 1%Extreme weather
- 0%Security
51% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 224,000 reported delay minutes here, that single category outweighs weather by 38 to one. The split is drawn from 223,790 reported delay minutes.
Cancellations sit at 1.29% against a national 1.89%, which is ordinary. Diversions add another 0.22%.
7.9% 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.
13,973 flights sit behind these numbers, which is a large enough sample that the headline rate is not moving on noise. Where a sub-group falls below 30 flights the site shows a dash instead of a percentage.
Put together: the calendar is the biggest lever here, not the carrier or the hour. March runs 87.8% on time and July 62.3%, a swing of 26 points. If the dates move at all, move them out of July before you think about anything else. 13,762 completed flights over 12 months sit behind that.
Common questions
Delta Air Lines at SFO
How often is Delta Air Lines at SFO delayed?
About one flight in four arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 24.2% of the 13,973 flights in this analysis, against 22.7% nationally. Delayed flights are late by about an hour on average.
Which airline is most reliable on Delta Air Lines at SFO?
United Airlines leads at 79.8% on time across 62,048 flights. Southwest Airlines is at the other end on 54.8%, a gap of 25 points. Sample size matters as much as the percentage: a rate built from a few hundred flights moves around far more than one built from ten thousand.
What time of day has the fewest delays on Delta Air Lines at SFO?
The 5am–8am departure window is the strongest at 92.8% on time. The 2pm–5pm window is the weakest at 66.7%, 26 points behind. Later departures inherit delays from earlier flights the same aircraft has already flown, which is why the curve slopes the way it does.
How bad are July delays on Delta Air Lines at SFO?
July is the weakest month at 62.3% on time, compared with 87.8% in March. Across the year that is 26 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.
Related
Where to go next
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.