Route reliability record
SAN→BWI
San Diego to Baltimore
- Flights
- 1,142
- Period
- July 2025 to June 2026
- Distance
- 2,295 mi
- Carriers
- 1
This route lands a B, 2 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 45 minutes on average. That is a workable record, not a spotless one. That rests on 1,142 SAN to BWI flights, with a median arrival 4 minutes early.
Best time to fly SAN to BWI: a 5am–8am departure, ideally on a Saturday. Flights in that window arrived on time 90.9% of the time and Saturday flights 90.8%, against 79.4% 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
79.4%
Arrivals under 15 minutes late, of 1,122 completed flights
Avg delay
47 min
Across delayed arrivals only, not all flights
Cancelled
1.49%
National rate is 1.81%
Best carrier
Southwest
79.4% on time across 1,142 flights
These figures cover 1,142 flights between July 2025 and June 2026. The median arrival is 4 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 SAN to BWI
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 |
|---|---|---|---|---|---|
| Southwest Airlines | 1,142 | 79.4% | 47 min | 1.49% | B |
Best ways to make this trip
The most reliable ways to fly San Diego 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. 1 of the top 2 use a different airport at one end.
| Option | Airline | Success | On time | Cancelled | Best departure | Most punctual flight |
|---|---|---|---|---|---|---|
| 1. SAN → IADSan Diego to Washington | United Airlines | 89.1% | 89.5% | 0.48% | 11am–2pm, Tue | UA 2129 21:45 |
| 2. SAN → BWISan Diego to Baltimore | Southwest Airlines | 78.2% | 79.4% | 1.49% | 5am–8am, 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 36 points, against half a point between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am336 flights90.9%
- 8am–11am19 flights—
- 11am–2pm346 flights63.2%
- 2pm–5pm76 flights55.4%
- 5pm–8pm—
- 8pm–5am365 flights88.4%
Scale runs 45% to 95%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 90.9% of the time, against 55.4% for the afternoon window. That is 36 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 365 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 27 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 63.4% on time, 27 points below September, the best at 90.1%. 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. May was the busiest month here, with 106 flights.
Across the week, Saturday is the strongest day at 90.8% on time and Thursday the weakest at 71.9%. 19 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 52% of the 11,000 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.
- 52%Late-arriving aircraft
- 28%Carrier
- 18%National Airspace System
- 1%Security
- 0%Extreme weather
52% 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 11,000 reported delay minutes here, that single category outweighs weather by 52 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 10,863 reported delay minutes.
The practical consequence: the 5am–8am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 90.9% on time here.
Cancellations sit at 1.49% against a national 1.81%, which is ordinary. Diversions add another 0.26%.
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 2,295 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 75.4% on time across 1,141 flights, 4 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 4 points of difference.
The sample behind these figures is 1,142 flights, enough that the headline rate is stable to within roughly a point. The hour-block and month splits divide that further, so read the thinner bars with more caution than the headline.
Work out the risk of missing a connection in BWI after this flight
What to do with this
Booking this route
Put together: the calendar is the biggest lever here, not the carrier or the hour. September runs 90.1% on time and June 63.4%, a swing of 27 points. If the dates move at all, move them out of June before you think about anything else. 1,122 completed flights over 12 months sit behind that.
Common questions
SAN to BWI questions
How often is SAN 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 20.6% of the 1,142 flights in this analysis, against 22.4% nationally. Delayed flights are late by roughly 45 minutes on average.
How reliable is SAN to BWI compared with the rest of the country?
79.4% of flights arrive on time here against a national 77.6%, a difference of 2 points in its favour. That is worth a B on this site's grading scale.
What time of day has the fewest delays on SAN to BWI?
The 5am–8am departure window is the strongest at 90.9% on time. The 2pm–5pm window is the weakest at 55.4%, 36 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 SAN to BWI?
June is the weakest month at 63.4% on time, compared with 90.1% in September. Across the year that is 27 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 SAN — the return legseparate record
- San Diego International (SAN) delay statistics
- Baltimore/Washington International Thurgood Marshall (BWI) delay statistics
- SAN to SFO, a related route65.0%
- ATL to BWI, a related route75.6%
- SAN to DEN, a related route79.2%
- Southwest Airlines on-time record79.4%
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.04 million flight records
Direction matters. SAN to BWI and BWI to SAN 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.