Carrier route record
UABWI→SFO
United Airlines · Baltimore to San Francisco
- Flights
- 668
- 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 BWI to SFO lands a B+, level with the national rate of 77.3%. Roughly one flight in five arrives 15 minutes late or worse, and those flights are late by about 50 minutes on average. That rests on 668 flights, with a median arrival 7 minutes early.
The US average over the same twelve months is 77.3%, so there is little to separate United on BWI to SFO from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
77.9%
Arrivals under 15 minutes late, of 660 completed flights
Avg delay
50 min
Across delayed arrivals only, not all flights
Cancelled
0.90%
National rate is 1.89%
Whole route
68.5%
Every carrier on BWI to SFO, 1,033 flights
These figures cover 668 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.
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Carrier by carrier
United against every carrier on BWI to SFO
United flew 668 of the 1,033 flights on BWI to SFO, most of the route. Its 77.9% on time is 9 points better than the route as a whole, which runs 68.5%. Ranked by on-time rate it is first of two carriers on the route, where the range runs from United at 77.9% to Southwest at 51.4%.
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) | 668 | 77.9% | 50 min | 0.90% | B+ |
| Southwest Airlines | 365 | 51.4% | 55 min | 0.82% | F+ |
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 matters more here than the choice of carrier. The gap between the best and worst window is 29 points, against half a point between the best and worst carrier.
- 5am–8am180 flights88.8%
- 8am–11am213 flights90.0%
- 11am–2pm—
- 2pm–5pm—
- 5pm–8pm275 flights61.4%
- 8pm–5am—
Scale runs 55% to 95%. Rows with fewer than 30 flights show a dash.
The 5pm–8pm window is where this operation falls apart: 61.4% on time, against 90.0% for the 8am–11am slot. By evening the aircraft flying these rotations have absorbed a full day of small delays and there is no slack left to recover in. The 5pm–8pm window is the busiest, with 275 flights scheduled in it.
Across the year
United on BWI to SFO through the year
June is the worst month at 58.5% on time, 34 points below October, the best at 92.0%. 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. October was the busiest month here, with 75 flights.
Across the week, Tuesday is the strongest day at 88.1% on time and Thursday the weakest at 70.8%, a spread of 17 points.
Arrival by arrival
How late United on BWI to SFO runs when it is late
United on BWI to SFO often beats the schedule: 220 of 660 completed flights, 33%, arrived 15 minutes or more early. The 146 late arrivals split 55 under half an hour, 54 between 30 and 60 minutes, and 37 an hour or more.
- 15+ min early220 flights33.3%
- Within 15 min294 flights44.5%
- 15–29 min late55 flights8.3%
- 30–59 min late54 flights8.2%
- 1–2 hours late29 flights4.4%
- 2+ hours late8 flights1.2%
Scale runs 0% to 100%.
Share of 660 completed flights by arrival against schedule.
18 of 118 late departures made up the time and arrived on time, 15% of them. In the other direction, 46 flights left on time yet arrived 15 minutes late or more, so that delay built up after pushback: in the air, in a holding pattern or on the ground at SFO.
The worst days
Worst days for United on BWI to SFO
The latest arrival of the period was on 4 March 2026, 9 hours 25 minutes behind schedule; most of its delay minutes were filed as a late-arriving aircraft. On three of the five worst days the largest share was filed as national airspace system delay.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 4 March 2026 | 9 hours 25 minutes | Late-arriving aircraft |
| 13 March 2026 | 4 hours 46 minutes | Extreme weather |
| 11 June 2026 | 3 hours 11 minutes | National Airspace System |
| 11 April 2026 | 2 hours 53 minutes | National Airspace System |
| 20 April 2026 | 2 hours 35 minutes | National Airspace System |
Delay causes
Why United runs late on this route
National Airspace System accounts for 53% of the 7,359 delay minutes carriers reported here, and the remaining four split what is left.
- 53%National Airspace System
- 21%Late-arriving aircraft
- 20%Carrier
- 7%Extreme weather
53% 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 3,871 minutes out of 7,359, against a national NAS share of 21%. The split is drawn from 7,359 reported delay minutes.
Cancellations sit at 0.90% against a national 1.89%, which is ordinary. Diversions add another 0.30%.
Connections and stage length
What a delay here costs
5.6% 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 about 50 minutes, which a normal layover absorbs.
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 90.8% on time across 669 flights, 13 points above 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. 668 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 BWI to SFO
Put together: treat all of this as provisional. 668 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 77.9% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 660 completed flights over 12 months sit behind that.
Related
Where to go next
- BWI to SFO, every carrier
- United on SFO to BWI, the return leg
- Southwest Airlines on BWI to SFO51.4%
- United Airlines network-wide record
- Baltimore/Washington International Thurgood Marshall (BWI) delay statistics
- San Francisco International (SFO) delay statistics
- The best time of day to fly, according to 7.05 million flight records
- Worst months to fly in the US, ranked by the data
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.