Route reliability record
CLE→IAH
Cleveland to Houston
- Flights
- 823
- Period
- July 2025 to June 2026
- Distance
- 1,091 mi
- Carriers
- 1
This route earns an A+. Close to nine flights in ten arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 12 points better than the national rate of 77.6%. When something does go wrong the average delay runs about an hour. That rests on 823 CLE to IAH flights, with a median arrival 17 minutes early.
Best time to fly CLE to IAH: a 5am–8am departure, ideally on a Wednesday. Flights in that window arrived on time 92.8% of the time and Wednesday flights 92.4%, against 90.0% for the route overall.
Set against the rest of the country, this route's record is 12 points better than the US average of 77.6%. That gap is worth roughly 124 fewer late arrivals for every thousand flights.
Key figures
On time
90.0%
Arrivals under 15 minutes late, of 822 completed flights
Avg delay
58 min
Across delayed arrivals only, not all flights
Cancelled
0.00%
National rate is 1.81%
Best carrier
United
90.0% on time across 823 flights
These figures cover 823 flights between July 2025 and June 2026. The median arrival is 17 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 CLE to IAH
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 | 823 | 90.0% | 58 min | 0.00% | A+ |
Flight by flight
Flights on CLE to IAH
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 is the single lever a traveller controls, and it moves the odds more than most people expect. Each bar below is the on-time rate for flights scheduled to leave inside that window, across 823 flights.
- 5am–8am361 flights92.8%
- 8am–11am1 flights—
- 11am–2pm—
- 2pm–5pm365 flights89.0%
- 5pm–8pm96 flights83.3%
- 8pm–5am—
Scale runs 75% to 100%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 92.8% of the time, against 83.3% for the evening window. That is 10 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 2pm–5pm 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 16 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.
December is the weak month at 80.3% on time, against 96.7% in September. Winter delays cluster: a single storm system can account for most of a month's shortfall, so an average December hides both very good weeks and genuinely unflyable days. July was the busiest month here, with 88 flights.
Across the week, Wednesday is the strongest day at 92.4% on time and Tuesday the weakest at 87.7%. 5 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. National Airspace System accounts for 44% of the 4,786 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.
- 44%National Airspace System
- 39%Carrier
- 15%Late-arriving aircraft
- 2%Extreme weather
The largest share of delay minutes, 39%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. Unlike weather, that is a management outcome, and it is the category where the gap between two carriers on the same schedule is genuinely earned. It accounts for 1,861 of the 4,786 delay minutes reported here. The split is drawn from 4,786 reported delay minutes.
44% 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 2,115 minutes out of 4,786, against a national NAS share of 21%.
Cancellations are rare at 0.00%, below the national 1.81% and low enough to earn the plus on the grade. Almost no flights are called off; the risk here is arriving late, not not arriving.
Connections and stage length
What a delay here actually costs
Badly late arrivals are rare here: only 2.6% land an hour or more behind schedule, against 8.1% nationally. Connections built on this flight are about as safe as US domestic connections get, though a cancelled flight still ignores every layover you give it.
The 1,091 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 84.3% on time across 824 flights, 6 points below 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. 823 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 IAH after this flight
What to do with this
Booking this route
Put together: treat all of this as provisional. 823 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 90.0% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 822 completed flights over 12 months sit behind that.
Common questions
CLE to IAH questions
How often is CLE to IAH delayed?
About one flight in ten arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 10.0% of the 823 flights in this analysis, against 22.4% nationally. Delayed flights are late by about an hour on average.
How reliable is CLE to IAH compared with the rest of the country?
90.0% of flights arrive on time here against a national 77.6%, a difference of 12 points in its favour. That is worth a A+ on this site's grading scale.
What time of day has the fewest delays on CLE to IAH?
The 5am–8am departure window is the strongest at 92.8% on time. The 5pm–8pm window is the weakest at 83.3%, 10 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 December delays on CLE to IAH?
December is the weakest month at 80.3% on time, compared with 96.7% in September. Across the year that is 16 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
- IAH to CLE — the return legseparate record
- Cleveland Hopkins International (CLE) delay statistics
- George Bush Intercontinental (IAH) delay statistics
- CLE to ORD, a related route74.6%
- ORD to IAH, a related route75.0%
- CLE to ATL, a related route85.4%
- United Airlines on-time record90.0%
- The best time of day to fly, according to 7.04 million flight records
- Worst months to fly in the US, ranked by the data
Direction matters. CLE to IAH and IAH to CLE 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.