Route reliability record
IAD→BNA
Washington to Nashville
- Flights
- 998
- Period
- September 2025 to August 2026
- Distance
- 542 mi
- Carriers
- 4
This route lands a B+, 4 points better than the national rate of 77.3%. About one flight in five arrives 15 minutes late or worse, and those flights are late by a little over an hour on average. That rests on 998 IAD to BNA flights, with a median arrival 7 minutes early.
Best time to fly IAD to BNA: a 8am–11am departure, ideally on a Monday. Flights in that window arrived on time 90.0% of the time and Monday flights 84.7%, against 81.0% for the route overall.
The US average over the same twelve months is 77.3%, 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 988 completed flights
Avg delay
79 min
Across delayed arrivals only, not all flights
Cancelled
0.80%
National rate is 1.89%
Best carrier
United
81.3% on time across 927 flights
These figures cover 998 flights between September 2025 and August 2026. The median arrival is 7 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 IAD to BNA
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 Airlinesthin sample | 1 | 100.0% | — | 0.00% | A+ |
| Republic Airwaysthin sample | 38 | 89.2% | 59 min | 0.00% | A+ |
| United Airlines | 927 | 81.3% | 78 min | 0.76% | B+ |
| Allegiant Airthin sample | 32 | 61.3% | 94 min | 3.12% | D− |
Flight by flight
Flights on IAD to BNA
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.
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Best ways to make this trip
The most reliable ways to fly Washington to Nashville
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. 4 of the top 5 use a different airport at one end.
| Option | Airline | Success | On time | Cancelled | Best departure | Most punctual flight |
|---|---|---|---|---|---|---|
| 1. IAD → BNAWashington to Nashville | United Airlines | 80.7% | 81.3% | 0.76% | 8am–11am, Mon (route) | UA 2264 17:55 |
| 2. DCA → BNAWashington to Nashville | Republic Airways | 79.8% | 81.8% | 2.44% | 5am–8am, Sat | YX 4686 11:34 |
| 3. BWI → BNABaltimore to Nashville | Southwest Airlines | 77.6% | 79.0% | 1.82% | 5am–8am, Mon (route) | — |
| 4. DCA → BNAWashington to Nashville | Southwest Airlines | 72.7% | 74.4% | 2.23% | 5am–8am, Sat | — |
| 5. DCA → BNAWashington to Nashville | PSA Airlines | 54.8% | 60.1% | 8.77% | 8am–11am, 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 16 points, against half a point between the best and worst carrier.
- 5am–8am—
- 8am–11am271 flights90.0%
- 11am–2pm339 flights83.0%
- 2pm–5pm22 flights—
- 5pm–8pm355 flights73.8%
- 8pm–5am11 flights—
Scale runs 65% to 95%. Rows with fewer than 30 flights show a dash.
Book the morning departure. Flights leaving between 8am–11am arrive on time 90.0% of the time, against 73.8% for the evening window. That is 16 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 5pm–8pm window is the busiest, with 355 flights scheduled in it.
Explore
Filter IAD to BNA 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 IAD to BNA, the best departure window is 8am–11am at 90.0% on time and the worst is 5pm–8pm at 73.8%, a wide gap of 16.2 points. All US flights leaving 8am–11am ran 83.9%.
- 5–8am—
- 8–11am90.0%
- 11am–2pm83.0%
- 2–5pm—
- 5–8pm73.8%
- 8pm–5am—
best all US flightsScale 60% to 95%. Cells under 30 flights show a dash.
Across the year
When delays peak on this route
This route's year swings by 24 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.
July is the worst month at 69.5% on time, 24 points below April, the best at 93.3%. 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 98 flights.
Across the week, Monday is the strongest day at 84.7% on time and Sunday the weakest at 76.0%, a spread of 9 points.
Delay causes
Why this route gets delayed
Late-arriving aircraft accounts for 44% of the 15,000 delay minutes carriers reported here, and the remaining four split what is left.
- 44%Late-arriving aircraft
- 25%National Airspace System
- 22%Carrier
- 9%Extreme weather
44% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 15,000 reported delay minutes here, that single category outweighs weather by 5 to one. The split is drawn from 14,760 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 90.0% on time here.
Cancellations are rare at 0.80%, 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
7.7% 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 a little over an hour, which a normal layover absorbs.
The 542 miles between these two airports put this in the middle of the US network, around two and a half to three hours of block time. That is enough cruise to absorb a ten-minute late pushback and not enough to absorb thirty.
The return leg is a different operation and performs like one: it runs 77.5% on time across 997 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.
One caution: this is a thin sample. 998 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 BNA after this flight
What to do with this
Booking this route
Put together: treat all of this as provisional. 998 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. 988 completed flights over 12 months sit behind that.
Common questions
IAD to BNA questions
How often is IAD to BNA 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 998 flights in this analysis, against 22.7% nationally. Delayed flights are late by a little over an hour on average.
How reliable is IAD to BNA compared with the rest of the country?
81.0% of flights arrive on time here against a national 77.3%, a difference of 4 points in its favour. That is worth a B+ on this site's grading scale.
What time of day has the fewest delays on IAD to BNA?
The 8am–11am departure window is the strongest at 90.0% on time. The 5pm–8pm window is the weakest at 73.8%, 16 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 July delays on IAD to BNA?
July is the weakest month at 69.5% on time, compared with 93.3% in April. Across the year that is 24 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
- BNA to IAD — the return legseparate record
- Washington Dulles International (IAD) delay statistics
- Nashville International (BNA) delay statistics
- IAD to ATL, a related route78.0%
- ORD to BNA, a related route69.2%
- IAD to DEN, a related route83.1%
- Southwest Airlines on-time record100.0%
- Republic Airways on-time record89.2%
- United Airlines on-time record81.3%
- 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. IAD to BNA and BNA to IAD 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.