Route reliability record
IAH→RSW
Houston to Fort Myers
- Flights
- 877
- Period
- July 2025 to June 2026
- Distance
- 861 mi
- Carriers
- 1
This route earns a B+. More than four flights in five arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 7 points better than the national rate of 77.6%. When something does go wrong the average delay runs about an hour. That rests on 877 IAH to RSW flights, with a median arrival 11 minutes early.
Best time to fly IAH to RSW: a 5am–8am departure, ideally on a Thursday. Flights in that window arrived on time 94.4% of the time and Thursday flights 90.6%, against 84.3% for the route overall.
Set against the rest of the country, this route's record is 7 points better than the US average of 77.6%. That gap is worth roughly 67 fewer late arrivals for every thousand flights.
Key figures
On time
84.3%
Arrivals under 15 minutes late, of 871 completed flights
Avg delay
65 min
Across delayed arrivals only, not all flights
Cancelled
0.11%
National rate is 1.81%
Best carrier
United
84.3% on time across 877 flights
These figures cover 877 flights between July 2025 and June 2026. The median arrival is 11 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 IAH to RSW
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 | 877 | 84.3% | 65 min | 0.11% | B+ |
Flight by flight
Flights on IAH to RSW
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.
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 26 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–8am197 flights94.4%
- 8am–11am—
- 11am–2pm365 flights81.4%
- 2pm–5pm—
- 5pm–8pm264 flights83.7%
- 8pm–5am51 flights68.6%
Scale runs 60% to 100%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 94.4% of the time, against 68.6% for the overnight window. That is 26 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 365 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 30 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 66.7% on time, 30 points below February, the best at 96.2%. 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. January was the busiest month here, with 93 flights.
Across the week, Thursday is the strongest day at 90.6% on time and Sunday the weakest at 78.0%. 13 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 8,898 reported delay minutes.
- 38%Late-arriving aircraft
- 33%Carrier
- 21%National Airspace System
- 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 8,898 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 8,898 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 94.4% on time here.
Cancellations are rare at 0.11%, 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
6.3% 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 about an hour, which a normal layover absorbs.
The 861 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 87.8% on time across 878 flights, 4 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 4 points of difference.
One caution: this is a thin sample. 877 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 RSW after this flight
What to do with this
Booking this route
Put together: treat all of this as provisional. 877 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 84.3% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 871 completed flights over 12 months sit behind that.
Common questions
IAH to RSW questions
How often is IAH to RSW 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 15.7% of the 877 flights in this analysis, against 22.4% nationally. Delayed flights are late by about an hour on average.
How reliable is IAH to RSW compared with the rest of the country?
84.3% of flights arrive on time here against a national 77.6%, a difference of 7 points in its favour. That is worth a B+ on this site's grading scale.
What time of day has the fewest delays on IAH to RSW?
The 5am–8am departure window is the strongest at 94.4% on time. The 8pm–5am window is the weakest at 68.6%, 26 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 IAH to RSW?
July is the weakest month at 66.7% on time, compared with 96.2% in February. Across the year that is 30 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
- RSW to IAH — the return legseparate record
- George Bush Intercontinental (IAH) delay statistics
- Southwest Florida International (RSW) delay statistics
- IAH to ORD, a related route74.8%
- ORD to RSW, a related route76.1%
- IAH to DFW, a related route75.0%
- United Airlines on-time record84.3%
- 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. IAH to RSW and RSW to IAH 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.