Carrier performance at one airport
DL→SFO
Delta Air Lines at San Francisco International
- Departures
- 13,817
- Period
- July 2025 to June 2026
- Routes
- 9
- Rank here
- #2 of 9
Delta Air Lines at San Francisco lands a B, about a point better than the national rate of 77.6%. About one flight in five arrive 15 minutes late or worse, and those flights are late by about an hour on average. That is a workable record, not a spotless one. That rests on 13,817 flights, of which United Airlines flew 60,681 at 81.1% on time.
Measured against the airport rather than the country, Delta Air Lines runs about a point ahead of the 77.3% 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
78.7%
13,624 completed departures
Avg delay
68 min
Across delayed flights only
Cancelled
1.19%
At SFO, this carrier only
Rank here
#2
Of 9 carriers clearing the floor at SFO
These figures cover 14,000 flights between July 2025 and June 2026. The median arrival is 8 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 81.1% of the time; Southwest Airlines manages 59.0%. Sample sizes sit next to every figure, because a two-point gap across 9,408 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| United Airlines | 60,681 | 81.1% | 59 min | 0.55% | B+ |
| Delta Air Lines (this page) | 13,817 | 78.7% | 68 min | 1.19% | B |
| JetBlue Airways | 4,397 | 78.6% | 75 min | 1.61% | B |
| American Airlines | 11,833 | 77.9% | 106 min | 1.88% | B |
| Alaska Airlines | 10,554 | 76.3% | 55 min | 1.07% | B |
| SkyWest Airlines | 32,078 | 76.3% | 74 min | 1.26% | B |
| Hawaiian Airlines | 507 | 75.1% | 67 min | 1.97% | B |
| Frontier Airlines | 3,407 | 65.2% | 83 min | 1.97% | C |
| Southwest Airlines | 9,408 | 59.0% | 59 min | 0.82% | D+ |
The spread between United and Southwest is 22 points, wide enough that it should decide the booking. On a hundred trips that is 22 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 | 2,407 | 83.0% | 68 min | 0.66% | B+ |
| SFO to LAX · Los Angeles | 2,373 | 73.6% | 65 min | 1.56% | C |
| SFO to JFK · New York | 2,229 | 79.9% | 69 min | 1.57% | B |
| SFO to SLC · Salt Lake City | 1,708 | 78.1% | 77 min | 0.88% | B+ |
| SFO to MSP · Minneapolis | 1,445 | 83.3% | 64 min | 0.97% | B+ |
| SFO to DTW · Detroit | 1,388 | 78.2% | 53 min | 0.86% | B+ |
| SFO to SEA · Seattle | 924 | 83.6% | 74 min | 1.73% | B |
| SFO to BOS · Boston | 899 | 75.1% | 73 min | 1.45% | B |
| SFO to AUS · Austin | 444 | 61.0% | 73 min | 1.58% | D |
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 23 points, against 22 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am3,087 flights93.2%
- 8am–11am1,719 flights82.2%
- 11am–2pm3,454 flights70.7%
- 2pm–5pm2,033 flights72.9%
- 5pm–8pm1,182 flights71.8%
- 8pm–5am2,342 flights77.1%
Scale runs 60% to 100%. Rows with fewer than 30 flights show a dash.
The weak window here is the middle of the day, not the evening: 11am–2pm runs 70.7% on time against 93.2% for 5am–8am. That shape usually means a departure bank rather than an accumulating delay, so the recovery later in the afternoon is real rather than noise. The 11am–2pm window is the busiest, with 3,454 flights scheduled in it.
Across the year
Seasonal pattern
June is the worst month at 64.5% on time, 23 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. June was the busiest month here, with 1,266 flights.
Delay causes
What holds this operation up
- 52%Late-arriving aircraft
- 32%Carrier
- 15%National Airspace System
- 1%Extreme weather
- 0%Security
52% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. That is a cascade, and cascades start small and grow through the day. Across 197,000 reported delay minutes here, that single category outweighs weather by 47 to one. It is the strongest argument for booking the first departure of the morning, when the aircraft has been sitting at the gate overnight with nothing to inherit. The split is drawn from 196,958 reported delay minutes.
Cancellations sit at 1.19% against a national 1.81%, which is ordinary. Diversions add another 0.20%.
7.2% 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 are the about an hour kind, which a normal layover absorbs.
13,817 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 June 64.5%, a swing of 23 points. If the dates move at all, move them out of June before you think about anything else. 13,624 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 five arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 21.3% of the 13,817 flights in this analysis, against 22.4% 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 81.1% on time across 60,681 flights. Southwest Airlines is at the other end on 59.0%, a gap of 22 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 93.2% on time. The 11am–2pm window is the weakest at 70.7%, 23 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 June delays on Delta Air Lines at SFO?
June is the weakest month at 64.5% on time, compared with 87.8% in March. Across the year that is 23 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
- Delta Air Lines network-wide record
- San Francisco International (SFO) all carriers
- SFO to ATL route record83.0%
- SFO to LAX route record73.6%
- SFO to JFK route record79.9%
- SFO to SLC route record78.1%
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.04 million flight records
Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Updated monthly. How this data is collected.