Route reliability record
CLE→IAH
Cleveland to Houston
- Flights
- 814
- Period
- September 2025 to August 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 14 points better than the national rate of 77.3%. When something does go wrong the average delay runs about an hour. That rests on 814 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 96.6%, against 90.8% for the route overall.
Set against the rest of the country, this route's record is 14 points better than the US average of 77.3%. That gap is worth roughly 135 fewer late arrivals for every thousand flights.
Key figures
On time
90.8%
Arrivals under 15 minutes late, of 812 completed flights
Avg delay
63 min
Across delayed arrivals only, not all flights
Cancelled
0.00%
National rate is 1.89%
Best carrier
United
90.8% on time across 814 flights
These figures cover 814 flights between September 2025 and August 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.
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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 | 814 | 90.8% | 63 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.
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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 814 flights.
- 5am–8am335 flights92.8%
- 8am–11am6 flights—
- 11am–2pm26 flights—
- 2pm–5pm344 flights89.5%
- 5pm–8pm103 flights86.3%
- 8pm–5am—
Scale runs 80% to 100%. Rows with fewer than 30 flights show a dash.
The early departures do better, though not dramatically: 92.8% on time for the 5am–8am window against 86.3% for 5pm–8pm. Worth taking if the schedule allows, not worth an extra connection. The 2pm–5pm window is the busiest, with 344 flights scheduled in it.
Explore
Filter CLE to IAH 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 CLE to IAH, the best departure window is 5am–8am at 92.8% on time and the worst is 5pm–8pm at 86.3%, a real gap of 6.5 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am92.8%
- 8–11am—
- 11am–2pm—
- 2–5pm89.5%
- 5–8pm86.3%
- 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 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 89 flights.
Across the week, Wednesday is the strongest day at 96.6% on time and Sunday the weakest at 88.1%, a spread of 9 points.
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 4,709 reported delay minutes.
- 39%National Airspace System
- 31%Carrier
- 27%Late-arriving aircraft
- 3%Extreme weather
39% 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 1,848 minutes out of 4,709, against a national NAS share of 21%. The split is drawn from 4,709 reported delay minutes.
Cancellations are rare at 0.00%, below the national 1.89% 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 3.4% land an hour or more behind schedule, against 8.3% 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.
The return leg is a different operation and performs like one: it runs 85.1% on time across 815 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. 814 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. 814 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 90.8% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 812 completed flights over 12 months sit behind that.
Common questions
CLE to IAH questions
How often is CLE to IAH delayed?
Roughly 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 9.2% of the 814 flights in this analysis, against 22.7% nationally. Delayed flights are late by about an hour on average.
How reliable is CLE to IAH compared with the rest of the country?
90.8% of flights arrive on time here against a national 77.3%, a difference of 14 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 86.3%, 7 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 route74.5%
- ORD to IAH, a related route76.0%
- CLE to ATL, a related route84.6%
- United Airlines on-time record90.8%
- The most punctual routes in the US, and the least
- 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, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.