Route reliability record
IAD→FLL
Washington to Fort Lauderdale
- Flights
- 760
- Period
- July 2025 to June 2026
- Distance
- 901 mi
- Carriers
- 2
This route lands a B+, 5 points better than the national rate of 77.6%. About one flight in six arrives 15 minutes late or worse, and those flights are late by a little over an hour on average. That is a workable record, not a spotless one. That rests on 760 IAD to FLL flights, with a median arrival 9 minutes early.
Best time to fly IAD to FLL: a 8am–11am departure, ideally on a Tuesday. Flights in that window arrived on time 89.5% of the time and Tuesday flights 88.2%, against 82.9% for the route overall.
Set against the rest of the country, this route's record is 5 points better than the US average of 77.6%. That gap is worth roughly 53 fewer late arrivals for every thousand flights.
Key figures
On time
82.9%
Arrivals under 15 minutes late, of 754 completed flights
Avg delay
69 min
Across delayed arrivals only, not all flights
Cancelled
0.53%
National rate is 1.81%
Best carrier
United
84.4% on time across 719 flights
These figures cover 760 flights between July 2025 and June 2026. The median arrival is 9 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 IAD to FLL
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 |
|---|---|---|---|---|---|
| United Airlines | 719 | 84.4% | 67 min | 0.56% | B+ |
| Frontier Airlinesthin sample | 41 | 56.1% | 86 min | 0.00% | D+ |
Flight by flight
Flights on IAD to FLL
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.
Best ways to make this trip
The most reliable ways to fly Washington to Fort Lauderdale
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 → FLLWashington to Fort Lauderdale | United Airlines | 83.9% | 84.4% | 0.56% | 8am–11am, Tue (route) | UA 1825 08:15 |
| 2. BWI → MIABaltimore to Miami | American Airlines | 78.5% | 80.4% | 2.32% | 5am–8am, Mon | AA 1183 06:00 |
| 3. BWI → PBIBaltimore to West Palm Beach | Southwest Airlines | 76.7% | 77.7% | 1.30% | 8am–11am, Wed | — |
| 4. DCA → PBIWashington to West Palm Beach | American Airlines | 75.8% | 77.2% | 1.79% | 5am–8am, Wed | — |
| 5. DCA → MIAWashington to Miami | American Airlines | 75.6% | 77.4% | 2.28% | 5am–8am, Tue | — |
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. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am—
- 8am–11am250 flights89.5%
- 11am–2pm142 flights82.1%
- 2pm–5pm1 flights—
- 5pm–8pm366 flights78.9%
- 8pm–5am1 flights—
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 89.5% of the time, against 78.9% 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 366 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 17 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 73.3% on time, 17 points below September, the best at 90.0%. 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 84 flights.
Across the week, Tuesday is the strongest day at 88.2% on time and Friday the weakest at 78.3%. 10 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 8,957 reported delay minutes.
- 38%Late-arriving aircraft
- 34%National Airspace System
- 20%Carrier
- 8%Extreme weather
38% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. That is a cascade, and cascades start small and grow through the day. Across 8,957 reported delay minutes here, that single category outweighs weather by 5 to one. It is the strongest argument for booking the first departure of the morning, when the aircraft has been sitting at the gate overnight with nothing to inherit. The split is drawn from 8,957 reported delay minutes.
34% of delay minutes are charged to the National Airspace System: air traffic volume, runway configuration, ground stops. No carrier can price its way out of that, which is why airport choice moves the number here more than carrier choice does. That is 3,051 minutes out of 8,957, against a national NAS share of 21%.
Cancellations are rare at 0.53%, below the national 1.81% 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
6.9% 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 a little over an hour, which a normal layover absorbs.
The 901 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. It is also long enough that the aircraft usually flies three or four legs a day rather than six, which slows how fast delay compounds.
The return leg is a different operation and performs like one: it runs 86.0% on time across 761 flights, 3 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 3 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 FLL 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 82.9% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 754 completed flights over 12 months sit behind that.
Common questions
IAD to FLL questions
How often is IAD to FLL 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 17.1% of the 760 flights in this analysis, against 22.4% nationally. Delayed flights are late by a little over an hour on average.
How reliable is IAD to FLL compared with the rest of the country?
82.9% of flights arrive on time here against a national 77.6%, 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 FLL?
The 8am–11am departure window is the strongest at 89.5% on time. The 5pm–8pm window is the weakest at 78.9%, 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 July delays on IAD to FLL?
July is the weakest month at 73.3% on time, compared with 90.0% in September. Across the year that is 17 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
- FLL to IAD — the return legseparate record
- Washington Dulles International (IAD) delay statistics
- Fort Lauderdale-Hollywood International (FLL) delay statistics
- IAD to ATL, a related route79.2%
- ATL to FLL, a related route70.7%
- IAD to DEN, a related route81.7%
- United Airlines on-time record84.4%
- Frontier Airlines on-time record56.1%
- 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. IAD to FLL and FLL 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, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.