Route reliability record
IAD→JAX
Washington to Jacksonville
- Flights
- 760
- Period
- September 2025 to August 2026
- Distance
- 631 mi
- Carriers
- 3
This route lands a B+, 5 points better than the national rate of 77.3%. About one flight in six arrives 15 minutes late or worse, and those flights are late by an hour and a half on average. That rests on 760 IAD to JAX flights, with a median arrival 12 minutes early.
Best time to fly IAD to JAX: a 8am–11am departure, ideally on a Wednesday. Flights in that window arrived on time 88.7% of the time and Wednesday flights 90.6%, against 82.5% for the route overall.
Set against the rest of the country, this route's record is 5 points better than the US average of 77.3%. That gap is worth roughly 52 fewer late arrivals for every thousand flights.
Key figures
On time
82.5%
Arrivals under 15 minutes late, of 753 completed flights
Avg delay
84 min
Across delayed arrivals only, not all flights
Cancelled
0.79%
National rate is 1.89%
Best carrier
United
83.8% on time across 643 flights
These figures cover 760 flights between September 2025 and August 2026. The median arrival is 12 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 JAX
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 |
|---|---|---|---|---|---|
| Republic Airwaysthin sample | 59 | 87.9% | 27 min | 1.69% | A |
| United Airlines | 643 | 83.8% | 80 min | 0.78% | B+ |
| Allegiant Airthin sample | 58 | 62.1% | 120 min | 0.00% | D+ |
Flight by flight
Flights on IAD to JAX
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.
Timetable by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.
Best ways to make this trip
The most reliable ways to fly Washington to Jacksonville
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. 2 of the top 3 use a different airport at one end.
| Option | Airline | Success | On time | Cancelled | Best departure | Most punctual flight |
|---|---|---|---|---|---|---|
| 1. IAD → JAXWashington to Jacksonville | United Airlines | 83.1% | 83.8% | 0.78% | 8am–11am, Wed (route) | UA 2084 09:00 |
| 2. BWI → JAXBaltimore to Jacksonville | Southwest Airlines | 74.8% | 76.0% | 1.64% | 8am–11am, Wed | — |
| 3. DCA → JAXWashington to Jacksonville | American Airlines | 71.1% | 72.7% | 2.16% | 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 11 points, against half a point between the best and worst carrier.
- 5am–8am—
- 8am–11am294 flights88.7%
- 11am–2pm25 flights—
- 2pm–5pm37 flights83.8%
- 5pm–8pm404 flights77.7%
- 8pm–5am—
Scale runs 70% to 95%. Rows with fewer than 30 flights show a dash.
Book the morning departure. Flights leaving between 8am–11am arrive on time 88.7% of the time, against 77.7% for the evening window. That is 11 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 404 flights scheduled in it.
Explore
Filter IAD to JAX 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 JAX, the best departure window is 8am–11am at 88.7% on time and the worst is 5pm–8pm at 77.7%, a wide gap of 11.0 points. All US flights leaving 8am–11am ran 83.9%.
- 5–8am—
- 8–11am88.7%
- 11am–2pm—
- 2–5pm83.8%
- 5–8pm77.7%
- 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.
August is the worst month at 66.7% on time, 24 points below September, the best at 91.1%. 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. March was the busiest month here, with 94 flights.
Across the week, Wednesday is the strongest day at 90.6% on time and Friday the weakest at 77.9%, a spread of 13 points.
Delay causes
Why this route gets delayed
Late-arriving aircraft accounts for 43% of the 11,000 delay minutes carriers reported here, and the remaining four split what is left.
- 43%Late-arriving aircraft
- 25%Carrier
- 20%National Airspace System
- 12%Extreme weather
Extreme weather accounts for 12% of delay minutes, well above the single-digit share typical across the system. Weather delays are lumpy: they arrive as whole bad days rather than as a steady drag, so the monthly strip above is the more useful view of the risk. The national share is 6%, so this operation carries roughly 2.1 times the usual weather exposure. The split is drawn from 11,072 reported delay minutes.
43% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 11,000 reported delay minutes here, that single category outweighs weather by 3 to one.
Cancellations are rare at 0.79%, 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
6.6% 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 an hour and a half, which a normal layover absorbs.
The 631 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 88.8% on time across 759 flights, 6 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 6 points of difference.
One caution: this is a thin sample. 760 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 JAX after this flight
What to do with this
Booking this route
Put together: treat all of this as provisional. 760 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 82.5% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 753 completed flights over 12 months sit behind that.
Common questions
IAD to JAX questions
How often is IAD to JAX delayed?
About one flight in six arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 17.5% of the 760 flights in this analysis, against 22.7% nationally. Delayed flights are late by an hour and a half on average.
How reliable is IAD to JAX compared with the rest of the country?
82.5% of flights arrive on time here against a national 77.3%, a difference of 5 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 JAX?
The 8am–11am departure window is the strongest at 88.7% on time. The 5pm–8pm window is the weakest at 77.7%, 11 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 August delays on IAD to JAX?
August is the weakest month at 66.7% on time, compared with 91.1% in September. 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
- JAX to IAD — the return legseparate record
- Washington Dulles International (IAD) delay statistics
- Jacksonville International (JAX) delay statistics
- IAD to ATL, a related route78.0%
- ATL to JAX, a related route75.1%
- IAD to DEN, a related route83.1%
- Republic Airways on-time record87.9%
- United Airlines on-time record83.8%
- Allegiant Air on-time record62.1%
- 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 JAX and JAX 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.