Carrier route record
UASAN→IAD
United Airlines · San Diego to Washington
- Flights
- 1,041
- Period
- September 2025 to August 2026
- Share of route
- 74%
- Carriers
- 2
Historical statistics for September 2025 to August 2026, not live status. For today’s flights, check with United Airlines.
United on SAN to IAD earns an A+. Close to nine flights in ten arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 11 points better than the national rate of 77.3%. When something does go wrong the average delay runs a little over an hour. That rests on 1,041 flights, with a median arrival 12 minutes early.
Set against the rest of the country, United's SAN to IAD record is 11 points better than the US average of 77.3%. That gap is worth roughly 107 fewer late arrivals for every thousand flights.
Key figures
On time
88.0%
Arrivals under 15 minutes late, of 1,027 completed flights
Avg delay
81 min
Across delayed arrivals only, not all flights
Cancelled
0.77%
National rate is 1.89%
Whole route
87.6%
Every carrier on SAN to IAD, 1,402 flights
These figures cover 1,041 flights between September 2025 and August 2026. The median arrival is 12 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.
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Carrier by carrier
United against every carrier on SAN to IAD
United flew 1,041 of the 1,402 flights on SAN to IAD, most of the route. Its 88.0% on time is about level with the route as a whole at 87.6%. Ranked by on-time rate it is first of two carriers on the route, where the range runs from United at 88.0% to Alaska at 86.3%. One of those carriers flew fewer than 365 flights here, so treat their positions as rough.
Only one carrier clears this site's 365-flight floor here, so there is no comparison to draw. The table below is the full picture.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| United Airlines (this page) | 1,041 | 88.0% | 81 min | 0.77% | A+ |
| Alaska Airlinesthin sample | 361 | 86.3% | 57 min | 0.83% | A+ |
Flight by flight
United flight numbers on SAN to IAD
Timetable by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.
Departure window
When United runs best on this route
Departure time is the single lever a traveller controls, and it moves the odds more than most people expect. Each bar below is the on-time rate for flights scheduled to leave inside that window, across 1,041 flights.
- 5am–8am16 flights—
- 8am–11am336 flights89.1%
- 11am–2pm363 flights87.7%
- 2pm–5pm—
- 5pm–8pm—
- 8pm–5am326 flights87.3%
Scale runs 80% to 95%. Rows with fewer than 30 flights show a dash.
The 8am–11am window is the strongest at 89.1% on time. The full set of windows spans 2 points.
Across the year
United on SAN to IAD through the year
July is the worst month at 72.2% on time, 24 points below February, the best at 95.8%. 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 93 flights.
Across the week, Tuesday is the strongest day at 95.7% on time and Sunday the weakest at 83.9%, a spread of 12 points.
Arrival by arrival
How late United on SAN to IAD runs when it is late
United on SAN to IAD often beats the schedule: 464 of 1,027 completed flights, 45%, arrived 15 minutes or more early. The 123 late arrivals split 44 under half an hour, 45 between 30 and 60 minutes, and 34 an hour or more.
- 15+ min early464 flights45.2%
- Within 15 min440 flights42.8%
- 15–29 min late44 flights4.3%
- 30–59 min late45 flights4.4%
- 1–2 hours late21 flights2.0%
- 2+ hours late13 flights1.3%
Scale runs 0% to 100%.
Share of 1,027 completed flights by arrival against schedule.
30 of 119 late departures made up the time and arrived on time, 25% of them. 34 flights left on time and still arrived late.
The worst days
Worst days for United on SAN to IAD
The latest arrival of the period was on 2 January 2026, 13 hours 41 minutes behind schedule; most of its delay minutes were filed as extreme weather. On three of the five worst days the largest share was filed as carrier-caused (crew, maintenance, fuelling, baggage).
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 2 January 2026 | 13 hours 41 minutes | Extreme weather |
| 6 March 2026 | 13 hours 16 minutes | Carrier |
| 28 October 2025 | 12 hours 45 minutes | Carrier |
| 30 May 2026 | 12 hours 21 minutes | Extreme weather |
| 5 January 2026 | 11 hours 31 minutes | Carrier |
Delay causes
Why United runs late on this route
Carriers report a reason for every delay minute they cause, in five DOT categories. The split below is by minutes, not by number of flights, so a handful of very long weather delays weighs as much as many short ones. It covers 9,935 reported delay minutes.
- 40%Carrier
- 23%National Airspace System
- 22%Late-arriving aircraft
- 14%Extreme weather
Extreme weather accounts for 14% of delay minutes, well above the single-digit share typical across the system. Weather delays are lumpy: they arrive as whole bad days rather than as a steady drag, so the monthly strip above is the more useful view of the risk. The national share is 6%, so this operation carries roughly 2.4 times the usual weather exposure. The split is drawn from 9,935 reported delay minutes.
The largest share of delay minutes, 40%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 4,013 of the 9,935 delay minutes reported here.
Cancellations are rare at 0.77%, 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.
Connections and stage length
What a delay here costs
Badly late arrivals are rare here: only 3.3% land an hour or more behind schedule, against 8.3% nationally. Connections built on this flight are about as safe as US domestic connections get, though a cancelled flight still ignores every layover you give it.
At 2,253 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.
The return leg runs 86.1% on time across 1,041 flights, within 2 points of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.
One caution: this is a thin sample. 1,041 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 United on SAN to IAD
Put together: treat all of this as provisional. 1,041 flights over twelve months is enough to clear this site's floor and not enough to be confident to better than a couple of points. The 88.0% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 1,027 completed flights over 12 months sit behind that.
Related
Where to go next
- SAN to IAD, every carrier
- United on IAD to SAN, the return leg
- Alaska Airlines on SAN to IAD86.3%
- United Airlines network-wide record
- San Diego International (SAN) delay statistics
- Washington Dulles International (IAD) delay statistics
- Worst months to fly in the US, ranked by the data
- Late aircraft, weather, or the airline: what actually causes US flight delays
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.