Route reliability record

CLT→IAH

Charlotte to Houston

Flights: 2,348
Period: July 2025 to June 2026
Distance: 912 mi
Carriers: 4

This route lands a B, level with the national rate of 77.6%. Roughly one flight in four arrive 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 2,348 flights, of which United Airlines flew 394 at 85.8% on time.

The US average over the same twelve months is 77.6%, 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.

On time

77.6%

Arrivals under 15 minutes late, of 2,298 completed flights

Avg delay

74 min

Across delayed arrivals only, not all flights

Cancelled

1.96%

National rate is 1.81%

Best carrier

United

85.8% on time across 394 flights

These figures cover 2,348 flights between July 2025 and June 2026. Beyond the headline rate, 8.8% of arrivals land a full hour or more behind schedule. That is the number that wrecks a connection, and it is not visible in an on-time percentage alone.

Carrier by carrier

Which airline is most reliable on CLT to IAH

The choice of carrier is not cosmetic here. United Airlines arrives on time 85.8% of the time; American Airlines manages 76.1%. Sample sizes sit next to every figure, because a two-point gap across 1,623 flights means less than a ten-point one.

On-time performance by carrier on CLT to IAH
Airline	Flights	On time	Avg delay	Cancelled	Grade
United Airlines	394	85.8%	95 min	1.78%	A
American Airlines	1,623	76.1%	73 min	1.60%	B
Frontier Airlinesthin sample	216	75.6%	62 min	5.09%	B−
SkyWest Airlinesthin sample	115	74.3%	67 min	1.74%	C

United leads American by 10 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.

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 25 points, against 10 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am589 flights88.1%
8am–11am270 flights89.5%
11am–2pm340 flights82.5%
2pm–5pm461 flights69.8%
5pm–8pm442 flights65.0%
8pm–5am246 flights69.1%

Scale runs 55% 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 65.0% for the evening window. That is 25 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 5am–8am window is the busiest, with 589 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.

Darker means more delays. Figures are on-time percentages.September best, July worst

July is the worst month at 59.3% on time, 30 points below September, the best at 89.6%. 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 227 flights.

Across the week, Tuesday is the strongest day at 84.1% on time and Friday the weakest at 72.1%. 12 points is a smaller lever than departure hour, but it is free.

Delay causes

Why this route gets delayed

One category carries most of the weight here. Late-arriving aircraft accounts for 42% of the 38,000 delay minutes carriers reported, and the remaining four split what is left. The split is by minutes rather than by flights, so a few very long delays count for as much as many short ones.

Late-arriving aircraft
42%
Carrier
30%
National Airspace System
21%
Extreme weather
7%
Security
0%

42% 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 38,000 reported delay minutes here, that single category outweighs weather by 6 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 37,952 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 89.5% on time here.

Cancellations sit at 1.96% against a national 1.81%, which is ordinary. Diversions add another 0.17%.

Connections and stage length

What a delay here actually costs

8.8% of arrivals land an hour or more late, close to the national 8.1%. 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 are the a little over an hour kind, which a normal layover absorbs.

The 912 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 runs 79.5% on time across 2,348 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.

The sample behind these figures is 2,348 flights, enough that the headline rate is stable to within roughly a point. The hour-block and month splits divide that further, so read the thinner bars with more caution than the headline.

What to do with this

Booking this route

Put together: the calendar is the biggest lever here, not the carrier or the hour. September runs 89.6% on time and July 59.3%, a swing of 30 points. If the dates move at all, move them out of July before you think about anything else. 2,298 completed flights over 12 months sit behind that.

Common questions

CLT to IAH questions

How often is CLT to IAH delayed?

Roughly one flight in four arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 22.4% of the 2,348 flights in this analysis, against 22.4% nationally. Delayed flights are late by a little over an hour on average.

Which airline is most reliable on CLT to IAH?

United Airlines leads at 85.8% on time across 394 flights. American Airlines is at the other end on 76.1%, a gap of 10 points. Sample size matters as much as the percentage: a rate built from a few hundred flights moves around far more than one built from ten thousand.

What time of day has the fewest delays on CLT to IAH?

The 8am–11am departure window is the strongest at 89.5% on time. The 5pm–8pm window is the weakest at 65.0%, 25 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 CLT to IAH?

July is the weakest month at 59.3% on time, compared with 89.6% in September. 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.

Where to go next

Direction matters. CLT to IAH and IAH to CLT are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.

Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Updated monthly. How this data is collected.

Key figures