Route reliability record
BWI→SFO
Baltimore to San Francisco
- Flights
- 1,033
- Period
- September 2025 to August 2026
- Distance
- 2,457 mi
- Carriers
- 2
This route sits in the middle of the pack with a C+. About seven flights in ten arrive on time by the DOT's definition, 9 points worse than the national rate of 77.3%. The late ones land roughly 55 minutes behind schedule. That rests on 1,033 BWI to SFO flights, of which United Airlines flew 668 at 77.9% on time.
Best time to fly BWI to SFO: a 5am–8am departure, ideally on a Saturday. Flights in that window arrived on time 88.8% of the time and Saturday flights 79.0%, against 68.5% for the route overall.
The national on-time rate over the same period is 77.3%, so this route runs 9 points behind the country as a whole. Across a thousand flights that is about 88 extra late arrivals.
Key figures
On time
68.5%
Arrivals under 15 minutes late, of 1,020 completed flights
Avg delay
53 min
Across delayed arrivals only, not all flights
Cancelled
0.87%
National rate is 1.89%
Best carrier
United
77.9% on time across 668 flights
These figures cover 1,033 flights between September 2025 and August 2026. Beyond the headline rate, 8.4% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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Carrier by carrier
Which airline is most reliable on BWI to SFO
The choice of carrier is not cosmetic here. United Airlines arrives on time 77.9% of the time; Southwest Airlines manages 51.4%. Sample sizes sit next to every figure, because a two-point gap across 365 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| United Airlines | 668 | 77.9% | 50 min | 0.90% | B+ |
| Southwest Airlines | 365 | 51.4% | 55 min | 0.82% | F+ |
The spread between United and Southwest is 27 points, wide enough that it should decide the booking. On a hundred trips that is 27 more arrivals inside the on-time window.
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Best ways to make this trip
The most reliable ways to fly Baltimore to San Francisco
Every airline on this route and on the routes between nearby airports, ranked by how often a scheduled flight actually operated and arrived on time. 2 of the top 4 use a different airport at one end.
| Option | Airline | Success | On time | Cancelled | Best departure | Most punctual flight |
|---|---|---|---|---|---|---|
| 1. BWI → SFOBaltimore to San Francisco | United Airlines | 77.2% | 77.9% | 0.90% | 8am–11am, Tue | — |
| 2. IAD → SFOWashington to San Francisco | United Airlines | 76.9% | 77.5% | 0.71% | 5am–8am, Tue | UA 1095 06:30 |
| 3. DCA → SFOWashington to San Francisco | United Airlines | 74.3% | 74.8% | 0.69% | 5am–8am, Sat | UA 369 07:00 |
| 4. BWI → SFOBaltimore to San Francisco | Southwest Airlines | 51.0% | 51.4% | 0.82% | 8am–11am, Sat | — |
Success is the share of scheduled flights that operated and arrived less than 15 minutes late, so a cancelled flight counts against it. “(route)” means the best time comes from every carrier on the route rather than this airline alone.
Departure window
The best time of day to leave
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 49 points, against 27 points between the best and worst carrier.
- 5am–8am180 flights88.8%
- 8am–11am315 flights82.3%
- 11am–2pm58 flights53.4%
- 2pm–5pm58 flights50.0%
- 5pm–8pm357 flights56.8%
- 8pm–5am65 flights39.7%
Scale runs 30% to 95%.
The 8pm–5am window is where this operation falls apart: 39.7% on time, against 88.8% for the 5am–8am 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 357 flights scheduled in it.
Explore
Filter BWI to SFO by airline, time, month and day
Pick a breakdown and a carrier. The dashed mark on each row is the same slice for every US flight.
On BWI to SFO, the best departure window is 5am–8am at 88.8% on time and the worst is 8pm–5am at 39.7%, a wide gap of 49.1 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am88.8%
- 8–11am82.3%
- 11am–2pm53.4%
- 2–5pm50.0%
- 5–8pm56.8%
- 8pm–5am39.7%
best all US flightsScale 30% to 95%.
Across the year
When delays peak on this route
This route's year swings by 44 points from best month to worst, which is wide. An annual average tells you very little about the week you are actually flying, so read the strip rather than the headline if your dates are fixed.
June is the worst month at 41.0% on time, 44 points below October, the best at 84.9%. 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 106 flights.
Across the week, Saturday is the strongest day at 79.0% on time and Monday the weakest at 63.9%, a spread of 15 points.
Delay causes
Why this route gets delayed
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 17,000 reported delay minutes.
- 41%National Airspace System
- 29%Carrier
- 26%Late-arriving aircraft
- 4%Extreme weather
41% 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 6,950 minutes out of 17,000, against a national NAS share of 21%. The split is drawn from 16,959 reported delay minutes.
Cancellations are rare at 0.87%, 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 actually costs
8.4% 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 roughly 55 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 81.0% on time across 1,034 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. 1,033 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.
Work out the risk of missing a connection in SFO after this flight
What to do with this
Booking this route
Put together: treat all of this as provisional. 1,033 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 68.5% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 1,020 completed flights over 12 months sit behind that.
Common questions
BWI to SFO questions
How often is BWI to SFO delayed?
About one flight in three arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 31.5% of the 1,033 flights in this analysis, against 22.7% nationally. Delayed flights are late by roughly 55 minutes on average.
Which airline is most reliable on BWI to SFO?
United Airlines leads at 77.9% on time across 668 flights. Southwest Airlines is at the other end on 51.4%, a gap of 27 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 BWI to SFO?
The 5am–8am departure window is the strongest at 88.8% on time. The 8pm–5am window is the weakest at 39.7%, 49 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 June delays on BWI to SFO?
June is the weakest month at 41.0% on time, compared with 84.9% in October. Across the year that is 44 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
- SFO to BWI — the return legseparate record
- Baltimore/Washington International Thurgood Marshall (BWI) delay statistics
- San Francisco International (SFO) delay statistics
- United Airlines on BWI to SFO77.9%
- Southwest Airlines on BWI to SFO51.4%
- BWI to ATL, a related route79.9%
- LAX to SFO, a related route60.1%
- BWI to MCO, a related route75.5%
- United Airlines on-time record77.9%
- Southwest Airlines on-time record51.4%
- Same route, different airline: where the carrier you pick matters most
- The best time of day to fly, according to 7.05 million flight records
Direction matters. BWI to SFO and SFO to BWI are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
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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.