Route reliability record
IAH→DTW
Houston to Detroit
- Flights
- 2,088
- Period
- September 2025 to August 2026
- Distance
- 1,075 mi
- Carriers
- 5
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 2,088 IAH to DTW flights, with a median arrival 6 minutes early.
Best time to fly IAH to DTW: a 5am–8am departure, ideally on a Wednesday. Flights in that window arrived on time 89.0% of the time and Wednesday flights 81.9%, against 78.9% 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
78.9%
Arrivals under 15 minutes late, of 2,061 completed flights
Avg delay
74 min
Across delayed arrivals only, not all flights
Cancelled
1.10%
National rate is 1.89%
Best carrier
Delta
82.4% on time across 1,327 flights
These figures cover 2,088 flights between September 2025 and August 2026. The median arrival is 6 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 IAH to DTW
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 |
|---|---|---|---|---|---|
| Delta Air Lines | 1,327 | 82.4% | 72 min | 0.68% | B+ |
| Spirit Airlinesthin sample | 295 | 75.1% | 83 min | 3.39% | B− |
| Frontier Airlinesthin sample | 183 | 72.1% | 86 min | 1.64% | C |
| United Airlinesthin sample | 277 | 70.7% | 64 min | 0.36% | C+ |
| SkyWest Airlinesthin sample | 6 | 66.7% | 89 min | 0.00% | C+ |
Flight by flight
Flights on IAH to DTW
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 matters more here than the choice of carrier. The gap between the best and worst window is 20 points, against half a point between the best and worst carrier.
- 5am–8am491 flights89.0%
- 8am–11am28 flights—
- 11am–2pm375 flights81.8%
- 2pm–5pm562 flights78.6%
- 5pm–8pm332 flights71.0%
- 8pm–5am300 flights68.6%
Scale runs 60% to 95%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 89.0% of the time, against 68.6% for the overnight window. That is 20 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 562 flights scheduled in it.
Explore
Filter IAH to DTW 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 IAH to DTW, the best departure window is 5am–8am at 89.0% on time and the worst is 8pm–5am at 68.6%, a wide gap of 20.4 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am89.0%
- 8–11am—
- 11am–2pm81.8%
- 2–5pm78.6%
- 5–8pm71.0%
- 8pm–5am68.6%
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 21 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.
September is the best month on the calendar at 89.4% on time. Shoulder season thins the schedule and takes the summer weather with it, and the operation gets its margin back. March was the busiest month here, with 204 flights.
Across the week, Wednesday is the strongest day at 81.9% on time and Monday the weakest at 74.8%, a spread of 7 points.
Delay causes
Why this route gets delayed
Carrier accounts for 45% of the 32,000 delay minutes carriers reported here, and the remaining four split what is left.
- 45%Carrier
- 37%Late-arriving aircraft
- 13%National Airspace System
- 5%Extreme weather
- 0%Security
37% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 32,000 reported delay minutes here, that single category outweighs weather by 8 to one. The split is drawn from 32,146 reported delay minutes.
The largest share of delay minutes, 45%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 15,000 of the 32,000 delay minutes reported here.
Cancellations sit at 1.10% against a national 1.89%, which is ordinary. Diversions add another 0.19%.
Connections and stage length
What a delay here actually costs
6.2% 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 1,075 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 78.5% on time across 2,083 flights, within half a point 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 2,088 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.
Work out the risk of missing a connection in DTW after this flight
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 89.4% on time and March 68.8%, a swing of 21 points. If the dates move at all, move them out of March before you think about anything else. 2,061 completed flights over 12 months sit behind that.
Common questions
IAH to DTW questions
How often is IAH to DTW 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 21.1% of the 2,088 flights in this analysis, against 22.7% nationally. Delayed flights are late by a little over an hour on average.
How reliable is IAH to DTW compared with the rest of the country?
78.9% 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 IAH to DTW?
The 5am–8am departure window is the strongest at 89.0% on time. The 8pm–5am window is the weakest at 68.6%, 20 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 March delays on IAH to DTW?
March is the weakest month at 68.8% on time, compared with 89.4% in September. Across the year that is 21 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
- DTW to IAH — the return legseparate record
- George Bush Intercontinental (IAH) delay statistics
- Detroit Metropolitan Wayne County (DTW) delay statistics
- Delta Air Lines on IAH to DTW82.4%
- Spirit Airlines on IAH to DTW75.1%
- Frontier Airlines on IAH to DTW72.1%
- United Airlines on IAH to DTW70.7%
- IAH to ORD, a related route75.1%
- ORD to DTW, a related route71.1%
- IAH to DFW, a related route76.4%
- Delta Air Lines on-time record82.4%
- Spirit Airlines on-time record75.1%
- Frontier Airlines on-time record72.1%
- 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. IAH to DTW and DTW 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, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.