Route reliability record
BWI→SAN
Baltimore to San Diego
- Flights
- 1,165
- Period
- September 2025 to August 2026
- Distance
- 2,295 mi
- Carriers
- 1
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, 4 points worse than the national rate of 77.3%. The late ones land roughly 50 minutes behind schedule. That rests on 1,165 BWI to SAN flights, with a median arrival 1 minute early.
Best time to fly BWI to SAN: a 5am–8am departure, ideally on a Saturday. Flights in that window arrived on time 86.6% of the time and Saturday flights 78.0%, against 72.9% for the route overall.
The national on-time rate over the same period is 77.3%, so this route runs 4 points behind the country as a whole. Across a thousand flights that is about 44 extra late arrivals.
Key figures
On time
72.9%
Arrivals under 15 minutes late, of 1,142 completed flights
Avg delay
49 min
Across delayed arrivals only, not all flights
Cancelled
1.37%
National rate is 1.89%
Best carrier
Southwest
72.9% on time across 1,165 flights
These figures cover 1,165 flights between September 2025 and August 2026. On-time means an arrival less than 15 minutes after the scheduled gate time, the same threshold the Department of Transportation uses in its own reports. Cancelled and diverted flights are excluded from the on-time rate and counted separately, which is why the cancellation column matters on its own.
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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 | 1,165 | 72.9% | 49 min | 1.37% | C |
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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 | 85.5% | 86.1% | 0.67% | 8am–11am, Tue | UA 1930 09:00 |
| 2. BWI → SANBaltimore to San Diego | Southwest Airlines | 71.9% | 72.9% | 1.37% | 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 33 points, against half a point between the best and worst carrier.
- 5am–8am236 flights86.6%
- 8am–11am225 flights82.5%
- 11am–2pm118 flights79.3%
- 2pm–5pm223 flights53.9%
- 5pm–8pm179 flights73.4%
- 8pm–5am184 flights61.1%
Scale runs 45% to 90%.
Book the early departure. Flights leaving between 5am–8am arrive on time 86.6% of the time, against 53.9% for the afternoon window. That is 33 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 236 flights scheduled in it.
Explore
Filter BWI to SAN 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 SAN, the best departure window is 5am–8am at 86.6% on time and the worst is 2pm–5pm at 53.9%, a wide gap of 32.7 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am86.6%
- 8–11am82.5%
- 11am–2pm79.3%
- 2–5pm53.9%
- 5–8pm73.4%
- 8pm–5am61.1%
best all US flightsScale 45% to 95%.
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 78.0% on time and Sunday the weakest at 68.7%, a spread of 9 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 15,000 reported delay minutes.
- 40%Carrier
- 33%Late-arriving aircraft
- 24%National Airspace System
- 3%Extreme weather
- 1%Security
The largest share of delay minutes, 40%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 6,090 of the 15,000 delay minutes reported here. The split is drawn from 15,160 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 86.6% on time here.
Cancellations sit at 1.37% against a national 1.89%, which is ordinary. Diversions add another 0.60%.
Connections and stage length
What a delay here actually 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 roughly 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 76.6% on time across 1,182 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 1,165 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. 1,142 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 27.1% of the 1,165 flights in this analysis, against 22.7% nationally. Delayed flights are late by roughly 50 minutes on average.
How reliable is BWI to SAN compared with the rest of the country?
72.9% of flights arrive on time here against a national 77.3%, a difference of 4 points against it. That is worth a C 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 86.6% on time. The 2pm–5pm window is the weakest at 53.9%, 33 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 route79.9%
- SFO to SAN, a related route62.2%
- BWI to MCO, a related route75.5%
- Southwest Airlines on-time record72.9%
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.05 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, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.