Route reliability record
BWI→SAN
Baltimore to San Diego
- Flights
- 1,141
- Period
- July 2025 to June 2026
- Distance
- 2,295 mi
- Carriers
- 1
This route sits in the middle of the pack with a B. Close to three flights in four arrive on time by the DOT's definition, 2 points worse than the national rate of 77.6%. The late ones land about 50 minutes behind schedule. That rests on 1,141 BWI to SAN flights, with a median arrival 3 minutes early.
Best time to fly BWI to SAN: a 5am–8am departure, ideally on a Saturday. Flights in that window arrived on time 87.7% of the time and Saturday flights 80.8%, against 75.4% 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
75.4%
Arrivals under 15 minutes late, of 1,118 completed flights
Avg delay
51 min
Across delayed arrivals only, not all flights
Cancelled
1.40%
National rate is 1.81%
Best carrier
Southwest
75.4% on time across 1,141 flights
These figures cover 1,141 flights between July 2025 and June 2026. The median arrival is 3 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 BWI to SAN
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 | 1,141 | 75.4% | 51 min | 1.40% | B |
Best ways to make this trip
The most reliable ways to fly Baltimore to San Diego
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. IAD → SANWashington to San Diego | United Airlines | 86.8% | 87.1% | 0.38% | 8am–11am, Tue | UA 1930 09:00 |
| 2. BWI → SANBaltimore to San Diego | Southwest Airlines | 74.3% | 75.4% | 1.40% | 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 32 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–8am256 flights87.7%
- 8am–11am194 flights84.9%
- 11am–2pm128 flights81.7%
- 2pm–5pm200 flights55.8%
- 5pm–8pm191 flights79.4%
- 8pm–5am172 flights59.3%
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 87.7% of the time, against 55.8% for the afternoon window. That is 32 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 5am–8am window is the busiest, with 256 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 37 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 51.0% on time, 37 points below November, the best at 87.5%. 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 80.8% on time and Sunday the weakest at 69.8%. 11 points is a smaller lever than departure hour, but it is free.
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 14,000 reported delay minutes.
- 41%Carrier
- 32%Late-arriving aircraft
- 23%National Airspace System
- 3%Extreme weather
- 1%Security
The largest share of delay minutes, 41%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. Unlike weather, that is a management outcome, and it is the category where the gap between two carriers on the same schedule is genuinely earned. It accounts for 5,685 of the 14,000 delay minutes reported here. The split is drawn from 13,967 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 87.7% on time here.
Cancellations sit at 1.40% against a national 1.81%, which is ordinary. Diversions add another 0.61%.
Connections and stage length
What a delay here actually costs
6.1% of arrivals land an hour or more late, close to the national 8.1%. That is the figure that decides a connection, and it says 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 2,295 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 79.4% on time across 1,142 flights, 4 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 4 points of difference.
The sample behind these figures is 1,141 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 SAN 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. November runs 87.5% on time and June 51.0%, a swing of 37 points. If the dates move at all, move them out of June before you think about anything else. 1,118 completed flights over 12 months sit behind that.
Common questions
BWI to SAN questions
How often is BWI to SAN delayed?
About one flight in four arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 24.6% of the 1,141 flights in this analysis, against 22.4% nationally. Delayed flights are late by about 50 minutes on average.
How reliable is BWI to SAN compared with the rest of the country?
75.4% of flights arrive on time here against a national 77.6%, a difference of 2 points against it. That is worth a B on this site's grading scale.
What time of day has the fewest delays on BWI to SAN?
The 5am–8am departure window is the strongest at 87.7% on time. The 2pm–5pm window is the weakest at 55.8%, 32 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 SAN?
June is the weakest month at 51.0% on time, compared with 87.5% in November. Across the year that is 37 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
- SAN to BWI — the return legseparate record
- Baltimore/Washington International Thurgood Marshall (BWI) delay statistics
- San Diego International (SAN) delay statistics
- BWI to ATL, a related route80.6%
- SFO to SAN, a related route66.6%
- BWI to MCO, a related route75.6%
- Southwest Airlines on-time record75.4%
- 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. BWI to SAN and SAN 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, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.