Carrier performance at one airport
UA→SAN
United Airlines at San Diego International
- Departures
- 10,655
- Period
- September 2025 to August 2026
- Routes
- 7
- Rank here
- #3 of 8
United Airlines at San Diego lands a B+, 2 points better than the national rate of 77.3%. About one flight in five arrives 15 minutes late or worse, and those flights are late by a little over an hour on average. That rests on 10,655 flights, of which Delta Air Lines flew 9,581 at 86.3% on time.
Measured against the airport rather than the country, United Airlines runs 3 points ahead of the 76.3% weighted average across all carriers at SAN. That is the comparison worth making: every operator here works the same runways, the same airspace and the same weather.
Key figures
On time
79.7%
10,532 completed departures
Avg delay
69 min
Across delayed flights only
Cancelled
0.71%
At SAN, this carrier only
Rank here
#3
Of 8 carriers clearing the floor at SAN
These figures cover 11,000 flights between September 2025 and August 2026. The median arrival is 7 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 SAN, ranked
The choice of carrier is not cosmetic here. Delta Air Lines arrives on time 86.3% of the time; Southwest Airlines manages 70.6%. Sample sizes sit next to every figure, because a two-point gap across 39,067 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Delta Air Lines | 9,581 | 86.3% | 79 min | 1.17% | A |
| American Airlines | 9,387 | 80.6% | 103 min | 1.64% | B |
| United Airlines (this page) | 10,655 | 79.7% | 69 min | 0.71% | B+ |
| Alaska Airlines | 13,373 | 79.0% | 57 min | 1.35% | B |
| JetBlue Airways | 1,643 | 78.8% | 97 min | 3.16% | B− |
| SkyWest Airlines | 14,921 | 77.8% | 58 min | 2.01% | B |
| Frontier Airlines | 2,105 | 71.5% | 81 min | 1.95% | C |
| Southwest Airlines | 39,067 | 70.6% | 51 min | 0.92% | C+ |
JetBlue Airways cancels 3.2% of what it schedules here, the highest in the table. A cancelled flight never appears in an on-time rate, so read that column alongside the punctuality one rather than after it.
Route by route
Where United Airlines flies from SAN
United Airlines operates 7 routes out of SAN 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 |
|---|---|---|---|---|---|
| SAN to SFO · San Francisco | 2,666 | 67.2% | 57 min | 0.56% | C+ |
| SAN to DEN · Denver | 2,067 | 85.7% | 72 min | 0.63% | A+ |
| SAN to IAH · Houston | 1,686 | 83.9% | 70 min | 0.30% | B+ |
| SAN to ORD · Chicago | 1,677 | 80.0% | 78 min | 0.54% | B+ |
| SAN to EWR · Newark | 1,229 | 81.3% | 92 min | 2.12% | B |
| SAN to IAD · Washington | 1,041 | 88.0% | 81 min | 0.77% | A+ |
| SAN to LAX · Los Angelesthin sample | 289 | 88.9% | 77 min | 0.00% | A+ |
Flight by flight
United Airlines flight numbers from SAN
13 United Airlines flight numbers leaving SAN flew their main route often enough to have a record of their own. Grouped by destination.
- UA 519to DEN 18:5586.3%
- UA 682to DEN 16:1073.9%
- UA 2476to DEN 08:4588.7%
- UA 327to EWR 07:0578.8%
- UA 427to EWR 22:3081.6%
- UA 1827to EWR 22:2084.5%
- UA 1071to IAD 08:0089.0%
- UA 2129to IAD 21:4587.3%
- UA 2237to IAH 11:5877.8%
- UA 1779to ORD 14:1164.9%
- UA 2486to ORD 16:4178.5%
- UA 1763to SFO 13:3971.1%
- UA 2117to SFO 16:0073.3%
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 15 points, against 16 points between the best and worst carrier.
- 5am–8am2,041 flights86.4%
- 8am–11am1,890 flights83.2%
- 11am–2pm2,409 flights78.2%
- 2pm–5pm1,838 flights72.4%
- 5pm–8pm1,137 flights71.7%
- 8pm–5am1,340 flights84.1%
Scale runs 65% to 90%.
Book the early departure. Flights leaving between 5am–8am arrive on time 86.4% of the time, against 71.7% for the evening window. That is 15 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 2,409 flights scheduled in it.
Across the year
Seasonal pattern
August is the worst month at 67.6% on time, 20 points below February, the best at 87.3%. 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. August was the busiest month here, with 1,004 flights.
Delay causes
What holds this operation up
- 43%National Airspace System
- 34%Late-arriving aircraft
- 18%Carrier
- 6%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 63,000 minutes out of 147,000, against a national NAS share of 21%. The split is drawn from 147,415 reported delay minutes.
Cancellations are rare at 0.71%, below the national 1.89% 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.
6.8% 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 a little over an hour, which a normal layover absorbs.
The sample behind these figures is 10,655 flights, enough that the headline rate is stable to within roughly a point. The hour-block and month splits divide that further, so read the thinner bars with more caution than the headline.
Put together: the calendar is the biggest lever here, not the carrier or the hour. February runs 87.3% on time and August 67.6%, a swing of 20 points. If the dates move at all, move them out of August before you think about anything else. 10,532 completed flights over 12 months sit behind that.
Common questions
United Airlines at SAN
How often is United Airlines at SAN delayed?
About one flight in five arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 20.3% of the 10,655 flights in this analysis, against 22.7% nationally. Delayed flights are late by a little over an hour on average.
Which airline is most reliable on United Airlines at SAN?
Delta Air Lines leads at 86.3% on time across 9,581 flights. Southwest Airlines is at the other end on 70.6%, a gap of 16 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 United Airlines at SAN?
The 5am–8am departure window is the strongest at 86.4% on time. The 5pm–8pm window is the weakest at 71.7%, 15 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 August delays on United Airlines at SAN?
August is the weakest month at 67.6% on time, compared with 87.3% in February. Across the year that is 20 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.