Carrier route record
NKORD→IAH
Spirit Airlines · Chicago to Houston
- Flights
- 307
- Period
- July 2025 to June 2026
- Share of route
- 5%
- Carriers
- 8
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with Spirit Airlines.
Spirit on ORD to IAH draws a D−. Roughly one flight in three arrives at least 15 minutes late, and the typical late arrival is close to two hours behind schedule. Build slack into anything you connect to. That rests on 307 flights. The strongest carrier on the route with a full sample, United Airlines, flew 4,000 at 78.6% on time.
The national on-time rate over the same period is 77.6%, so Spirit on ORD to IAH runs 14 points behind the country as a whole. Across a thousand flights that is about 145 extra late arrivals.
Key figures
On time
63.1%
Arrivals under 15 minutes late, of 290 completed flights
Avg delay
102 min
Across delayed arrivals only, not all flights
Cancelled
5.54%
National rate is 1.81%
Whole route
75.0%
Every carrier on ORD to IAH, 6,077 flights
These figures cover 307 flights between July 2025 and June 2026. Beyond the headline rate, 19.3% 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
Spirit against every carrier on ORD to IAH
Spirit flew 307 of the 6,077 flights on ORD to IAH, about 5% of it. Its 63.1% on time is 12 points worse than the route as a whole, which runs 75.0%. Ranked by on-time rate it is number five of eight carriers on the route, where the range runs from United at 78.6% to SkyWest at 0.0%. Five of those carriers flew fewer than 365 flights here, so treat their positions as rough.
The choice of carrier is not cosmetic here. United Airlines arrives on time 78.6% of the time; American Airlines manages 60.6%. Sample sizes sit next to every figure, because a two-point gap across 798 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| United Airlines | 4,000 | 78.6% | 67 min | 0.65% | B+ |
| Republic Airwaysthin sample | 359 | 76.3% | 69 min | 2.51% | B |
| Frontier Airlinesthin sample | 249 | 76.0% | 96 min | 2.41% | B |
| Envoy Airthin sample | 358 | 74.4% | 63 min | 1.40% | C |
| Spirit Airlines (this page)thin sample | 307 | 63.1% | 102 min | 5.54% | D− |
| American Airlines | 798 | 60.6% | 84 min | 3.01% | D− |
| PSA Airlinesthin sample | 4 | 50.0% | 74 min | 0.00% | F+ |
| SkyWest Airlinesthin sample | 2 | 0.0% | 32 min | 0.00% | F+ |
American Airlines cancels 3.0% of what it schedules here, the highest in the table. A cancelled flight never appears in an on-time rate, so read that column alongside the punctuality one rather than after it.
Departure window
When Spirit runs best on this route
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 12 points, against 18 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am—
- 8am–11am66 flights68.3%
- 11am–2pm14 flights—
- 2pm–5pm83 flights56.8%
- 5pm–8pm11 flights—
- 8pm–5am133 flights63.9%
Scale runs 50% to 75%. Rows with fewer than 30 flights show a dash.
Book the morning departure. Flights leaving between 8am–11am arrive on time 68.3% of the time, against 56.8% for the afternoon window. That is 12 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 8pm–5am window is the busiest, with 133 flights scheduled in it.
Across the year
Spirit on ORD to IAH through the year
- Jul–Sep 2025108 flights70.3%
- Oct–Dec 202588 flights67.1%
- Jan–Mar 202688 flights59.5%
- Apr–Jun 202623 flights—
Scale runs 50% to 75%. Rows with fewer than 30 flights show a dash.
Monthly volumes are too low here to break the year into twelve reliable readings. What the twelve-month total says is 63.1% on time across 307 flights.
Spirit on ORD to IAH did not run the same all year. Its best quarter was Jul–Sep 2025 at 70.3% on time and its weakest Jan–Mar 2026 at 59.5%, a swing of 11 points on roughly 102 flights a quarter. The twelve-month rate averages over that, so if you are flying in a weak quarter the quarter's own figure is the better guide.
Across the week, Wednesday is the strongest day at 72.2% on time and Thursday the weakest at 51.2%. 21 points is a smaller lever than departure hour, but it is free.
Delay causes
Why Spirit runs late on this route
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 11,000 reported delay minutes.
- 37%Late-arriving aircraft
- 32%National Airspace System
- 23%Carrier
- 8%Extreme weather
37% 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 11,000 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 10,909 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 68.3% on time here.
Cancellations run at 5.54%, against 1.81% nationally. That is roughly one flight in twenty cancelled outright. A cancelled flight is invisible in every on-time figure on this page, so the punctuality numbers above describe only the flights that actually operated.
Connections and stage length
What a delay here costs
For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 19.3% of arrivals land a full hour or more behind schedule, against 8.1% nationally. A 45-minute layover does not survive that, and no amount of walking quickly changes it. Ninety minutes is the honest minimum here, and two hours if the onward flight is on a separate ticket.
The 925 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 66.0% on time across 305 flights, within 3 points of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.
One caution: this is a thin sample. 307 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.
What to do with this
Booking Spirit on ORD to IAH
Put together: the delay figures matter less here than the 5.54% cancellation rate. A late arrival costs you close to two hours; a cancelled flight costs you the day. Book the 8am–11am departure so there is still a schedule behind you if it goes wrong, and treat a same-day connection as optimistic. 290 completed flights over 12 months sit behind that.
Related
Where to go next
- ORD to IAH, every carrier
- Spirit on IAH to ORD, the return leg
- United Airlines on ORD to IAH78.6%
- Republic Airways on ORD to IAH76.3%
- Frontier Airlines on ORD to IAH76.0%
- Envoy Air on ORD to IAH74.4%
- American Airlines on ORD to IAH60.6%
- Spirit Airlines network-wide record
- Chicago O'Hare International (ORD) delay statistics
- George Bush Intercontinental (IAH) delay statistics
- The US routes with the most cancellations
- Why the first flight of the morning is statistically safest
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.