Carrier route record
UASFO→BWI
United Airlines · San Francisco to Baltimore
- Flights
- 669
- Period
- September 2025 to August 2026
- Share of route
- 65%
- Carriers
- 2
Historical statistics for September 2025 to August 2026, not live status. For today’s flights, check with United Airlines.
United on SFO to BWI 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 14 points better than the national rate of 77.3%. When something does go wrong the average delay runs roughly 45 minutes. That rests on 669 flights, with a median arrival 11 minutes early.
Set against the rest of the country, United's SFO to BWI record is 14 points better than the US average of 77.3%. That gap is worth roughly 135 fewer late arrivals for every thousand flights.
Key figures
On time
90.8%
Arrivals under 15 minutes late, of 664 completed flights
Avg delay
46 min
Across delayed arrivals only, not all flights
Cancelled
0.45%
National rate is 1.89%
Whole route
81.0%
Every carrier on SFO to BWI, 1,034 flights
These figures cover 669 flights between September 2025 and August 2026. The median arrival is 11 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 SFO to BWI
United flew 669 of the 1,034 flights on SFO to BWI, most of the route. Its 90.8% on time is 10 points better than the route as a whole, which runs 81.0%. Ranked by on-time rate it is first of two carriers on the route, where the range runs from United at 90.8% to Southwest at 63.0%.
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) | 669 | 90.8% | 46 min | 0.45% | A+ |
| Southwest Airlines | 365 | 63.0% | 50 min | 0.82% | D+ |
Flight by flight
United flight numbers on SFO to BWI
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Departure window
When United runs best on this route
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 14 points, against half a point between the best and worst carrier.
- 5am–8am—
- 8am–11am346 flights91.8%
- 11am–2pm36 flights77.8%
- 2pm–5pm—
- 5pm–8pm—
- 8pm–5am287 flights91.2%
Scale runs 70% to 95%. 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 77.8% on time against 91.8% for 8am–11am. 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 8am–11am window is the busiest, with 346 flights scheduled in it.
Across the year
United on SFO to BWI through the year
December is the weak month at 80.4% on time, against 96.4% in May. Winter delays cluster: a single storm system can account for most of a month's shortfall, so an average December hides both very good weeks and genuinely unflyable days. October was the busiest month here, with 74 flights.
Across the week, Tuesday is the strongest day at 93.8% on time and Thursday the weakest at 88.8%, a spread of 5 points.
Arrival by arrival
How late United on SFO to BWI runs when it is late
United on SFO to BWI often beats the schedule: 283 of 664 completed flights, 43%, arrived 15 minutes or more early. The 61 late arrivals split 26 under half an hour, 22 between 30 and 60 minutes, and 13 an hour or more.
- 15+ min early283 flights42.6%
- Within 15 min320 flights48.2%
- 15–29 min late26 flights3.9%
- 30–59 min late22 flights3.3%
- 1–2 hours late10 flights1.5%
- 2+ hours late3 flights0.5%
Scale runs 0% to 100%.
Share of 664 completed flights by arrival against schedule.
A late pushback is often recovered here: of 94 departures that left 15 minutes late or more, 48 still arrived on time. 15 flights left on time and still arrived late.
The worst days
Worst days for United on SFO to BWI
The latest arrival of the period was on 26 December 2025, 3 hours 48 minutes behind schedule; most of its delay minutes were filed as a late-arriving aircraft. The same cause led on four of the five worst days.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 26 December 2025 | 3 hours 48 minutes | Late-arriving aircraft |
| 24 November 2025 | 2 hours 36 minutes | Late-arriving aircraft |
| 18 October 2025 | 2 hours 11 minutes | Late-arriving aircraft |
| 25 January 2026 | 1 hour 58 minutes | Extreme weather |
| 25 December 2025 | 1 hour 51 minutes | Late-arriving aircraft |
Delay causes
Why United runs late on this route
Late-arriving aircraft accounts for 50% of the 2,832 delay minutes carriers reported here, and the remaining four split what is left.
- 50%Late-arriving aircraft
- 29%Carrier
- 17%National Airspace System
- 4%Extreme weather
50% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 2,832 reported delay minutes here, that single category outweighs weather by 12 to one. The split is drawn from 2,832 reported delay minutes.
The practical consequence: the 8am–11am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 91.8% on time here.
Cancellations are rare at 0.45%, 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 2.0% 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 2,457 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 is a different operation and performs like one: it runs 77.9% on time across 668 flights, 13 points below this direction. Departure banks, aircraft rotations and the congestion at each end all differ, so scoring the two directions together would average away a real 13 points of difference.
One caution: this is a thin sample. 669 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 SFO to BWI
Put together: treat all of this as provisional. 669 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 90.8% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 664 completed flights over 12 months sit behind that.
Related
Where to go next
- SFO to BWI, every carrier
- United on BWI to SFO, the return leg
- Southwest Airlines on SFO to BWI63.0%
- United Airlines network-wide record
- San Francisco International (SFO) delay statistics
- Baltimore/Washington International Thurgood Marshall (BWI) delay statistics
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.05 million flight records
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.