Carrier performance at one airport
DL→SFO
Delta Air Lines at San Francisco International
- Departures
- 13,738
- Period
- June 2025 to May 2026
- Routes
- 9
- Rank here
- #2 of 9
Delta Air Lines at San Francisco lands a B, 3 points better than the national rate of 77.4%. About one flight in five arrive 15 minutes late or worse, and those flights are late by a little over an hour on average. That is a workable record, not a spotless one. That rests on 13,738 flights, of which United Airlines flew 59,976 at 81.7% on time.
Measured against the airport rather than the country, Delta Air Lines runs 2 points ahead of the 78.3% 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
80.0%
13,545 completed departures
Avg delay
70 min
Across delayed flights only
Cancelled
1.21%
At SFO, this carrier only
Rank here
#2
Of 9 carriers clearing the floor at SFO
These figures cover 14,000 flights between June 2025 and May 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 81.7% of the time; Southwest Airlines manages 61.9%. Sample sizes sit next to every figure, because a two-point gap across 9,132 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| United Airlines | 59,976 | 81.7% | 59 min | 0.56% | B+ |
| Delta Air Lines (this page) | 13,738 | 80.0% | 70 min | 1.21% | B |
| JetBlue Airways | 4,340 | 80.0% | 75 min | 1.57% | B |
| American Airlines | 11,739 | 78.5% | 101 min | 1.88% | B |
| SkyWest Airlines | 32,426 | 77.8% | 74 min | 1.19% | B |
| Alaska Airlines | 10,622 | 76.1% | 55 min | 1.13% | B |
| Hawaiian Airlines | 593 | 75.6% | 65 min | 1.85% | B |
| Frontier Airlines | 3,323 | 65.5% | 83 min | 1.93% | C |
| Southwest Airlines | 9,132 | 61.9% | 58 min | 0.79% | D+ |
The spread between United and Southwest is 20 points, wide enough that it should decide the booking. On a hundred trips that is 20 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 | 2,409 | 83.0% | 70 min | 0.75% | B+ |
| SFO to LAX · Los Angeles | 2,374 | 75.2% | 66 min | 1.56% | B |
| SFO to JFK · New York | 2,230 | 80.6% | 73 min | 1.43% | B |
| SFO to SLC · Salt Lake City | 1,709 | 79.2% | 79 min | 0.82% | B+ |
| SFO to MSP · Minneapolis | 1,444 | 86.5% | 69 min | 1.04% | A |
| SFO to DTW · Detroit | 1,388 | 79.8% | 53 min | 1.01% | B |
| SFO to SEA · Seattle | 894 | 85.0% | 78 min | 1.90% | A |
| SFO to BOS · Boston | 883 | 77.9% | 80 min | 1.36% | B |
| SFO to AUS · Austin | 407 | 60.9% | 76 min | 1.72% | 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 22 points, against 20 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am3,116 flights93.3%
- 8am–11am1,630 flights83.8%
- 11am–2pm3,505 flights71.5%
- 2pm–5pm2,003 flights75.4%
- 5pm–8pm1,129 flights74.1%
- 8pm–5am2,355 flights79.0%
Scale runs 65% 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 71.5% on time against 93.3% 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.
Across the year
Seasonal pattern
Delays peak in May, when the on-time rate falls to 68.4%. March is the strongest month at 87.8%. Moving a flexible trip across that boundary buys 19 points.
Delay causes
What holds this operation up
- 50%Late-arriving aircraft
- 34%Carrier
- 15%National Airspace System
- 1%Extreme weather
- 0%Security
50% 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 191,000 reported delay minutes here, that single category outweighs weather by 38 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.
Cancellations sit at 1.21% against a national 1.80%, which is ordinary. Diversions add another 0.20%.
6.9% of arrivals land an hour or more late, close to the national 8.2%. 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 a little over an hour kind, which a normal layover absorbs.
13,738 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 May 68.4%, a swing of 19 points. If the dates move at all, move them out of May before you think about anything else.
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 20.0% of the 13,738 flights in this analysis, against 22.6% nationally. Delayed flights are late by a little over an hour on average.
Which airline is most reliable on Delta Air Lines at SFO?
United Airlines leads at 81.7% on time across 59,976 flights. Southwest Airlines is at the other end on 61.9%, a gap of 20 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 93.3% on time. The 11am–2pm window is the weakest at 71.5%, 22 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 May delays on Delta Air Lines at SFO?
May is the weakest month at 68.4% on time, compared with 87.8% in March. Across the year that is 19 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, June 2025 to May 2026. Updated monthly. How this data is collected.