Route reliability record
SFO→BWI
San Francisco to Baltimore
- Flights
- 1,085
- Period
- July 2025 to June 2026
- Distance
- 2,457 mi
- Carriers
- 2
This route lands a B+, 3 points better than the national rate of 77.6%. About one flight in five arrives 15 minutes late or worse, and those flights are late by roughly 50 minutes on average. That is a workable record, not a spotless one. That rests on 1,085 SFO to BWI flights, of which United Airlines flew 720 at 88.7% on time.
Best time to fly SFO to BWI: a 8am–11am departure, ideally on a Saturday. Flights in that window arrived on time 89.3% of the time and Saturday flights 87.0%, against 81.0% for the route overall.
The US average over the same twelve months is 77.6%, so there is little to separate this route from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
81.0%
Arrivals under 15 minutes late, of 1,073 completed flights
Avg delay
48 min
Across delayed arrivals only, not all flights
Cancelled
0.55%
National rate is 1.81%
Best carrier
United
88.7% on time across 720 flights
These figures cover 1,085 flights between July 2025 and June 2026. The median arrival is 6 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.
Carrier by carrier
Which airline is most reliable on SFO to BWI
The choice of carrier is not cosmetic here. United Airlines arrives on time 88.7% of the time; Southwest Airlines manages 65.7%. 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 | 720 | 88.7% | 49 min | 0.42% | A+ |
| Southwest Airlines | 365 | 65.7% | 47 min | 0.82% | C+ |
The spread between United and Southwest is 23 points, wide enough that it should decide the booking. On a hundred trips that is 23 more arrivals inside the on-time window.
Flight by flight
Flights on SFO to BWI
The flight numbers below flew this route at least 250 times in the period, busiest first. Each has its own record, with its schedule and delay causes.
Best ways to make this trip
The most reliable ways to fly San Francisco to Baltimore
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. SFO → BWISan Francisco to Baltimore | United Airlines | 88.3% | 88.7% | 0.42% | 8am–11am, Sun | UA 2664 09:09 |
| 2. SFO → IADSan Francisco to Washington | United Airlines | 83.2% | 83.8% | 0.74% | 5am–8am, Tue (route) | UA 1453 16:55 |
| 3. SFO → DCASan Francisco to Washington | United Airlines | 78.8% | 79.6% | 0.96% | 8am–11am, Sat | UA 1678 08:35 |
| 4. SFO → BWISan Francisco to Baltimore | Southwest Airlines | 65.2% | 65.7% | 0.82% | 8pm–5am, 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 12 points, against 23 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am—
- 8am–11am346 flights89.3%
- 11am–2pm36 flights77.8%
- 2pm–5pm—
- 5pm–8pm—
- 8pm–5am703 flights77.1%
Scale runs 70% to 95%. Rows with fewer than 30 flights show a dash.
Book the morning departure. Flights leaving between 8am–11am arrive on time 89.3% of the time, against 77.1% for the overnight window. That is 12 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 8pm–5am window is the busiest, with 703 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 26 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 66.3% on time, 26 points below March, the best at 92.2%. 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 115 flights.
Across the week, Saturday is the strongest day at 87.0% on time and Monday the weakest at 76.7%. 10 points is a smaller lever than departure hour, but it is free.
Delay causes
Why this route gets delayed
One category carries most of the weight here. Late-arriving aircraft accounts for 67% of the 9,700 delay minutes carriers reported, and the remaining four split what is left. The split is by minutes rather than by flights, so a few very long delays count for as much as many short ones.
- 67%Late-arriving aircraft
- 21%Carrier
- 11%National Airspace System
- 1%Extreme weather
67% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. That is a cascade, and cascades start small and grow through the day. Across 9,700 reported delay minutes here, that single category outweighs weather by 51 to one. It is the strongest argument for booking the first departure of the morning, when the aircraft has been sitting at the gate overnight with nothing to inherit. The split is drawn from 9,700 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 89.3% on time here.
Cancellations are rare at 0.55%, below the national 1.81% 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
Badly late arrivals are rare here: only 4.3% land an hour or more behind schedule, against 8.1% 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 71.2% on time across 1,086 flights, 10 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 10 points of difference.
One caution: this is a thin sample. 1,085 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 BWI after this flight
What to do with this
Booking this route
Put together: treat all of this as provisional. 1,085 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 81.0% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 1,073 completed flights over 12 months sit behind that.
Common questions
SFO to BWI questions
How often is SFO to BWI 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 19.0% of the 1,085 flights in this analysis, against 22.4% nationally. Delayed flights are late by roughly 50 minutes on average.
Which airline is most reliable on SFO to BWI?
United Airlines leads at 88.7% on time across 720 flights. Southwest Airlines is at the other end on 65.7%, a gap of 23 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 SFO to BWI?
The 8am–11am departure window is the strongest at 89.3% on time. The 8pm–5am window is the weakest at 77.1%, 12 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 SFO to BWI?
June is the weakest month at 66.3% on time, compared with 92.2% in March. Across the year that is 26 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
- BWI to SFO — the return legseparate record
- San Francisco International (SFO) delay statistics
- Baltimore/Washington International Thurgood Marshall (BWI) delay statistics
- United Airlines on SFO to BWI88.7%
- Southwest Airlines on SFO to BWI65.7%
- SFO to LAX, a related route73.9%
- ATL to BWI, a related route75.6%
- SFO to SEA, a related route73.7%
- United Airlines on-time record88.7%
- Southwest Airlines on-time record65.7%
- Same route, different airline: where the carrier you pick matters most
- Why the first flight of the morning is statistically safest
Direction matters. SFO to BWI and BWI to SFO 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, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.