Route reliability record
BNA→SAN
Nashville to San Diego
- Flights
- 1,092
- Period
- September 2025 to August 2026
- Distance
- 1,751 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, 5 points worse than the national rate of 77.3%. The late ones land roughly 45 minutes behind schedule. That rests on 1,092 BNA to SAN flights, with a median arrival 2 minutes early.
Best time to fly BNA to SAN: a 5am–8am departure, ideally on a Tuesday. Flights in that window arrived on time 91.3% of the time and Tuesday flights 80.7%, against 72.7% for the route overall.
The national on-time rate over the same period is 77.3%, so this route runs 5 points behind the country as a whole. Across a thousand flights that is about 46 extra late arrivals.
Key figures
On time
72.7%
Arrivals under 15 minutes late, of 1,077 completed flights
Avg delay
44 min
Across delayed arrivals only, not all flights
Cancelled
0.82%
National rate is 1.89%
Best carrier
Southwest
72.7% on time across 1,092 flights
These figures cover 1,092 flights between September 2025 and August 2026. The median arrival is 2 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.
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Carrier by carrier
Which airline is most reliable on BNA 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 | 1,092 | 72.7% | 44 min | 0.82% | C+ |
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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 28 points, against half a point between the best and worst carrier.
- 5am–8am197 flights91.3%
- 8am–11am160 flights84.6%
- 11am–2pm215 flights66.8%
- 2pm–5pm145 flights63.2%
- 5pm–8pm168 flights65.4%
- 8pm–5am207 flights64.6%
Scale runs 55% to 95%.
Book the early departure. Flights leaving between 5am–8am arrive on time 91.3% of the time, against 63.2% for the afternoon window. That is 28 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 11am–2pm window is the busiest, with 215 flights scheduled in it.
Explore
Filter BNA 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 BNA to SAN, the best departure window is 5am–8am at 91.3% on time and the worst is 2pm–5pm at 63.2%, a wide gap of 28.1 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am91.3%
- 8–11am84.6%
- 11am–2pm66.8%
- 2–5pm63.2%
- 5–8pm65.4%
- 8pm–5am64.6%
best all US flightsScale 55% to 95%.
Across the year
When delays peak on this route
This route's year swings by 38 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 50.0% on time, 38 points below January, the best at 87.9%. 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. August was the busiest month here, with 105 flights.
Across the week, Tuesday is the strongest day at 80.7% on time and Thursday the weakest at 62.8%, a spread of 18 points.
Delay causes
Why this route gets delayed
Late-arriving aircraft accounts for 45% of the 13,000 delay minutes carriers reported here, and the remaining four split what is left.
- 45%Late-arriving aircraft
- 31%Carrier
- 22%National Airspace System
- 1%Extreme weather
- 0%Security
45% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 13,000 reported delay minutes here, that single category outweighs weather by 45 to one. The split is drawn from 12,921 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 91.3% on time here.
Cancellations are rare at 0.82%, 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
6.2% 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 45 minutes, which a normal layover absorbs.
At 1,751 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 runs 72.6% on time across 1,107 flights, within half a point of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.
One caution: this is a thin sample. 1,092 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 SAN after this flight
What to do with this
Booking this route
Put together: treat all of this as provisional. 1,092 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 72.7% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 1,077 completed flights over 12 months sit behind that.
Common questions
BNA to SAN questions
How often is BNA to SAN delayed?
Roughly 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 27.3% of the 1,092 flights in this analysis, against 22.7% nationally. Delayed flights are late by roughly 45 minutes on average.
How reliable is BNA to SAN compared with the rest of the country?
72.7% of flights arrive on time here against a national 77.3%, a difference of 5 points against it. That is worth a C+ on this site's grading scale.
What time of day has the fewest delays on BNA to SAN?
The 5am–8am departure window is the strongest at 91.3% on time. The 2pm–5pm window is the weakest at 63.2%, 28 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 BNA to SAN?
June is the weakest month at 50.0% on time, compared with 87.9% in January. Across the year that is 38 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 BNA — the return legseparate record
- Nashville International (BNA) delay statistics
- San Diego International (SAN) delay statistics
- BNA to ORD, a related route70.9%
- SFO to SAN, a related route62.2%
- BNA to DCA, a related route71.3%
- Southwest Airlines on-time record72.7%
- 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. BNA to SAN and SAN to BNA 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.