Route reliability record
IAD→FLL
Washington to Fort Lauderdale
- Flights
- 802
- Period
- September 2025 to August 2026
- Distance
- 901 mi
- Carriers
- 2
This route lands a B, 2 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 802 IAD to FLL flights, with a median arrival 7 minutes early.
Best time to fly IAD to FLL: a 8am–11am departure, ideally on a Wednesday. Flights in that window arrived on time 89.1% of the time and Wednesday flights 87.0%, against 79.0% 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
79.0%
Arrivals under 15 minutes late, of 792 completed flights
Avg delay
79 min
Across delayed arrivals only, not all flights
Cancelled
1.00%
National rate is 1.89%
Best carrier
United
83.5% on time across 699 flights
These figures cover 802 flights between September 2025 and August 2026. Beyond the headline rate, 8.8% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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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 | 699 | 83.5% | 71 min | 0.57% | B+ |
| Frontier Airlinesthin sample | 103 | 47.5% | 95 min | 3.88% | F− |
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.
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 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 | 83.0% | 83.5% | 0.57% | 8am–11am, Wed | UA 1825 08:15 |
| 2. BWI → MIABaltimore to Miami | American Airlines | 78.8% | 80.6% | 2.29% | 5am–8am, Thu | AA 1183 06:00 |
| 3. BWI → PBIBaltimore to West Palm Beach | Southwest Airlines | 77.3% | 78.5% | 1.58% | 8am–11am, Wed | — |
| 4. DCA → MIAWashington to Miami | American Airlines | 75.9% | 77.7% | 2.28% | 5am–8am, Tue | — |
| 5. DCA → PBIWashington to West Palm Beach | American Airlines | 75.4% | 76.8% | 1.85% | 5am–8am, Wed | — |
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 17 points, against half a point between the best and worst carrier.
- 5am–8am—
- 8am–11am250 flights89.1%
- 11am–2pm142 flights82.1%
- 2pm–5pm1 flights—
- 5pm–8pm408 flights72.0%
- 8pm–5am1 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 89.1% of the time, against 72.0% for the evening window. That is 17 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 408 flights scheduled in it.
Explore
Filter IAD to FLL 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 FLL, the best departure window is 8am–11am at 89.1% on time and the worst is 5pm–8pm at 72.0%, a wide gap of 17.1 points. All US flights leaving 8am–11am ran 83.9%.
- 5–8am—
- 8–11am89.1%
- 11am–2pm82.1%
- 2–5pm—
- 5–8pm72.0%
- 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 34 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 55.7% on time, 34 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, Wednesday is the strongest day at 87.0% on time and Sunday the weakest at 74.8%, a spread of 12 points.
Delay causes
Why this route gets delayed
Late-arriving aircraft accounts for 47% of the 13,000 delay minutes carriers reported here, and the remaining four split what is left.
- 47%Late-arriving aircraft
- 33%National Airspace System
- 18%Carrier
- 3%Extreme weather
47% 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 16 to one. The split is drawn from 13,037 reported delay minutes.
33% 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 4,257 minutes out of 13,000, against a national NAS share of 21%.
Cancellations sit at 1.00% against a national 1.89%, which is ordinary. Diversions add another 0.25%.
Connections and stage length
What a delay here actually costs
8.8% 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 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.
The return leg runs 81.4% on time across 803 flights, within 2 points 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. 802 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. 802 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 79.0% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 792 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 five arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 21.0% of the 802 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 FLL compared with the rest of the country?
79.0% of flights arrive on time here against a national 77.3%, a difference of 2 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 89.1% on time. The 5pm–8pm window is the weakest at 72.0%, 17 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 55.7% on time, compared with 90.0% in September. Across the year that is 34 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
- United Airlines on IAD to FLL83.5%
- Frontier Airlines on IAD to FLL47.5%
- IAD to ATL, a related route78.0%
- ATL to FLL, a related route70.7%
- IAD to DEN, a related route83.1%
- United Airlines on-time record83.5%
- Frontier Airlines on-time record47.5%
- 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 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, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.