Route profile
IAH→ORD
Flight reliability, delays and best times to fly from Houston to Chicago, 925 miles.
Right now
Aviation weather is not currently a factor.
Aviation weather is not currently a factor.
Route reliability
July 2023 – July 2026
Better than 31% of comparable major US routes (4,598 compared)
Calculated from 17,013 flights. How this is calculated
IAH → ORD arrives on time 76.9% of the time; the return trip, ORD → IAH, arrives on time 77.0% of the time.
IAH → ORD spends 35.2 minutes on the ground on a 925-mile trip: 19.4 minutes from pushback to wheels-up at IAH and 15.8 minutes from touchdown to gate at ORD.
Source: US DOT Bureau of Transportation Statistics · Data covering July 2023 – July 2026
What stands out
The airline matters unusually much on this route, a wider carrier-to-carrier gap than 96% of 2,692 comparable routes.
United Airlines arrived on time 80.1% of the time, against 58.3% for Frontier Airlines, flying the exact same route.
Source: FlyerIntel analysis of US DOT BTS data · July 2023 – July 2026 · Ranked against every other route with the same kind of figure and at least 2,692 in the comparison.
Why IAH → ORD flights are cancelled
July 2023 – July 2026
IAH → ORD cancelled 242 of 17,013 scheduled flights — about 1 in every 70. The reason filed most often was extreme weather, 59.9% of the cancellations coded on this route — about 1 in every 117 scheduled flights.
Share of cancellations
Of 242 cancelled departures carrying a reason code.
What each reason means
Conditions the carrier judged severe enough to stop the flight: a blizzard, a hurricane, a line of thunderstorms.
145 cancellations, 59.9% of the total.
Crew, maintenance, aircraft cleaning, baggage or fueling: what BTS counts as within the carrier’s own control.
69 cancellations, 28.5% of the total.
Airport capacity, air traffic control flow programs, heavy traffic and ordinary bad weather. A system decision, not the airline’s.
28 cancellations, 11.6% of the total.
A terminal evacuation, a security breach, screening equipment failure, or screening queues over 29 minutes.
0 cancellations, 0.0% of the total.
Reason codes are the operating airline’s own filing with US DOT, not an independent finding of fault. Ordinary bad weather is filed under air traffic, so weather’s full share is larger than its bar.
242 coded cancellations were recorded on IAH → ORD; the section appears from 50.
When it goes wrong
July 2023 – July 2026
54 min late
against a median of 6 min early
IAH → ORD has an average that understates its risk: a typical arrival is 6 min early, but the worst tenth are 60 minutes worse than that. If the trip has something unmissable at the end of it, the median is the wrong number to plan against.
Percentiles over 17,013 operations; cancelled and diverted flights are counted separately.
Will your connection be tight enough?
Layovers at ORD after arriving from IAH.
| Connection time | Chance of missing | Reads as |
|---|---|---|
| 30 min | 39% | Likely to miss |
| 45 min | 22% | High risk |
| 60 min | 15% | High risk |
| 90 min | 9.0% | Some risk |
| 120 min | 6.0% | Some risk |
This is one leg of a connection. Gate changes and the next flight's own schedule matter too. And a connection can fail before delay is even the question — this route cancels 1.42% of the time and diverts 0.40% of the time, which a late arrival never shows up in.
Chance of missing is the share of 16,703 arrivals on this route that landed later than the connection time less 30 minutes to reach the next gate.
The worst tenth of arrivals on this route land at least 54 minutes late (90th-percentile gate arrival delay), over 17,013 operations.
Any other layover length: connection checker.
Best time to fly
IAH → ORD flights departing 5–9 AM arrived on time 89.5% of the time, against 63.5% for 3–6 PM departures, a gap of 26.0 percentage points.
By day and hour
On-time arrival rate for each weekday and scheduled departure hour, in local time at the departure airport (IAH).
Hour of departure matters more than day of the week: hourly averages sit a typical 10.2 points from the route-wide rate, weekday averages 1.9 points.
| Hour | Monday | Tuesday | Wednesday | Thursday | Friday | Saturday | Sunday |
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On-time rate, % · stronger color, fewer on time
- 50–59
- 60–69
- 70–79
- 80–89
- 90–99
- Fewer than 120 flights, not scored
Source: FlyerIntel analysis of US DOT BTS data · July 2023 – July 2026 · On time is arrival within 15 minutes of schedule. Cells round to whole percentages; the table shows one decimal.
No slot is named best or worst: too few reach 500 flights. Departures before 5 AM and after 10 PM (244 flights) are not drawn: no slot in those hours has enough flights to score.
View as tableHide table
| Hour | Monday | Tuesday | Wednesday | Thursday | Friday | Saturday | Sunday |
|---|---|---|---|---|---|---|---|
| 5 AM–6 AM | 90.2% on time133 flights | 99 flights, too few to score | 96 flights, too few to score | 92.9% on time127 flights | 95.5% on time134 flights | 89.0% on time129 flights | 95.8% on time124 flights |
| 6 AM–7 AM | 87.0% on time267 flights | 88.7% on time265 flights | 88.6% on time263 flights | 89.9% on time263 flights | 89.5% on time263 flights | 86.9% on time272 flights | 81.5% on time266 flights |
| 7 AM–8 AM | 92.9% on time157 flights | 87.9% on time161 flights | 88.0% on time161 flights | 91.6% on time155 flights | 91.1% on time160 flights | 90.0% on time163 flights | 86.1% on time165 flights |
| 8 AM–9 AM | 91.5% on time144 flights | 85.7% on time146 flights | 95.2% on time147 flights | 87.7% on time146 flights | 89.9% on time150 flights | 91.0% on time146 flights | 86.6% on time142 flights |
| 9 AM–10 AM | 79.7% on time120 flights | 117 flights, too few to score | 111 flights, too few to score | 88.5% on time123 flights | 86.3% on time124 flights | 113 flights, too few to score | 88.5% on time124 flights |
| 10 AM–11 AM | 76.1% on time122 flights | 84.0% on time120 flights | 114 flights, too few to score | 79.7% on time131 flights | 119 flights, too few to score | 100 flights, too few to score | 78.7% on time129 flights |
| 11 AM–12 PM | 73.6% on time150 flights | 75.2% on time128 flights | 75.0% on time120 flights | 77.9% on time155 flights | 71.3% on time138 flights | 78.5% on time136 flights | 69.1% on time154 flights |
| 12 PM–1 PM | 91 flights, too few to score | 99 flights, too few to score | 91 flights, too few to score | 101 flights, too few to score | 98 flights, too few to score | 84 flights, too few to score | 92 flights, too few to score |
| 1 PM–2 PM | 70.1% on time130 flights | 79.8% on time127 flights | 71.0% on time126 flights | 75.0% on time125 flights | 68.9% on time133 flights | 83 flights, too few to score | 71.5% on time127 flights |
| 2 PM–3 PM | 76.0% on time177 flights | 79.3% on time178 flights | 75.4% on time178 flights | 79.8% on time178 flights | 74.0% on time180 flights | 81.3% on time179 flights | 74.9% on time177 flights |
| 3 PM–4 PM | 9 flights, too few to score | 13 flights, too few to score | 12 flights, too few to score | 4 flights, too few to score | 7 flights, too few to score | 6 flights, too few to score | 10 flights, too few to score |
| 4 PM–5 PM | 72.3% on time216 flights | 66.0% on time157 flights | 66.3% on time181 flights | 60.6% on time227 flights | 57.8% on time223 flights | 67.9% on time164 flights | 58.8% on time227 flights |
| 5 PM–6 PM | 65.3% on time149 flights | 114 flights, too few to score | 67.2% on time122 flights | 61.5% on time145 flights | 56.7% on time145 flights | 113 flights, too few to score | 62.1% on time148 flights |
| 6 PM–7 PM | 57.6% on time228 flights | 66.2% on time229 flights | 67.0% on time222 flights | 60.5% on time232 flights | 60.3% on time228 flights | 66.8% on time225 flights | 55.5% on time231 flights |
| 7 PM–8 PM | 43 flights, too few to score | 33 flights, too few to score | 36 flights, too few to score | 36 flights, too few to score | 41 flights, too few to score | 43 flights, too few to score | 43 flights, too few to score |
| 8 PM–9 PM | 69.2% on time161 flights | 69.5% on time177 flights | 74.9% on time171 flights | 70.6% on time165 flights | 69.9% on time166 flights | 67.8% on time149 flights | 68.6% on time172 flights |
| 9 PM–10 PM | 72.0% on time183 flights | 79.1% on time130 flights | 72.9% on time146 flights | 78.1% on time159 flights | 69.3% on time180 flights | 75.6% on time139 flights | 66.7% on time163 flights |
By departure window
By departure hour
- 12 AM to 4 AM: too few flights to score
- 5 AM: 93.4% on time from 842 flights
- 6 AM: 87.4% on time from 1,859 flights
- 7 AM: 89.6% on time from 1,122 flights
- 8 AM: 89.7% on time from 1,021 flights
- 9 AM: 85.9% on time from 832 flights
- 10 AM: 79.4% on time from 835 flights
- 11 AM: 74.3% on time from 981 flights
- 12 PM: 84.2% on time from 656 flights
- 1 PM: 72.8% on time from 851 flights
- 2 PM: 77.2% on time from 1,247 flights
- 3 PM: too few flights to score
- 4 PM: 63.9% on time from 1,395 flights
- 5 PM: 63.0% on time from 936 flights
- 6 PM: 61.9% on time from 1,595 flights
- 7 PM: 71.8% on time from 275 flights
- 8 PM: 70.1% on time from 1,161 flights
- 9 PM: 73.0% on time from 1,100 flights
- 10 PM: 76.9% on time from 238 flights
- 11 PM: too few flights to score
Why IAH → ORD runs late
July 2023 – July 2026
the inbound aircraft was late, so this flight started late
airspace and airport capacity, including weather-driven flow control
crew, maintenance, boarding and fueling, all within the carrier’s control
weather severe enough to stop this flight specifically
screening or terminal security incidents
Share of the delay minutes US DOT attributed to each cause for IAH → ORD. Only delays of 15 minutes or more are attributed.
Late-arriving aircraft is the largest cause on IAH → ORD, at 39.6%: flights here mostly leave late because the plane came in late, and the day shows it: 5–9 AM departures arrived on time 89.5% of the time and 3–6 PM departures 63.5%.
How this route holds up in bad weather
July 2023 – July 2026
The harder-hit end is ORD, where the flight lands. Its figure counts departures from ORD, so it says more about how that airport copes than about this route. Bad weather cancels 5.5 times the normal rate at ORD against 3.4 times at IAH. Cancelled in bad weather against normal hours: IAH 4.1% against 1.2%, ORD 6.5% against 1.2%. Flights that did leave ORD in bad weather arrived on time 55.7% of the time, against 77.1% in normal hours.
Bad weather and normal hours at the airports
Scheduled departures, July 2023 – July 2026| Departures from | IAH | ORD |
|---|---|---|
| Cancelled in bad weather | 4.1% | 6.5% |
| Cancelled in normal hours | 1.2% | 1.2% |
| Arrived on time, bad weather | 63.8% | 55.7% |
| Arrived on time, normal hours | 78.6% | 77.1% |
| Departures in bad weather | 28,922 | 104,455 |
Of the carriers on this route, United Airlines (3.4% cancelled against 5.2% for the other carriers at IAH) cancelled the fewest departures from IAH in bad weather and Frontier Airlines (5.0% cancelled against 3.8% for the other carriers at IAH) the most. 2 more carriers fly this route but has too few bad-weather departures from IAH to compare.
This route’s airlines in bad weather at IAH
All departures from IAH| Airline | Bad-weather departures | Cancelled | Other carriers |
|---|---|---|---|
| United Airlines | 17,078 | 3.4%below the others | 5.2% |
| Spirit Airlines | 2,056 | 4.3%about level | 4.4% |
| American Airlines | 2,079 | 4.6%about level | 3.9% |
| Frontier Airlines | 915 | 5.0%above the others | 3.8% |
These are airport figures, not route figures: every scheduled departure from IAH and ORD, to any destination, in hours the weather report called bad. The airline rows count each carrier’s departures from IAH on every route.
Weather source and limits. In full: IAH (airlines), ORD, What Weather Costs Each Airport, Who Cancels More When the Weather Turns, Airports That Change Places When Weather Turns.
Airlines on this route
Carriers with at least 200 flights, by the airline that operated each one.
| Carrier | Flights | On time | Cancelled | Median delay | Severe |
|---|---|---|---|---|---|
| United Airlines | 11,770 | 80.1% | 0.91% | -6 min | 7.3% |
| American Airlines | 2,171 | 71.3% | 2.21% | -5 min | 12.8% |
| Spirit Airlines | 1,312 | 67.9% | 2.67% | -3 min | 12.8% |
| Envoy Air | 686 | 73.3% | 1.31% | -7 min | 10.2% |
| Republic Airways | 579 | 73.3% | 3.63% | -9 min | 14.0% |
| Frontier Airlines | 488 | 58.3% | 4.51% | 6 min | 23.0% |
United Airlines flew 69.2% of the 17,006 flights listed. Frontier Airlines cancelled 4.51% of its flights here against 0.91% for United Airlines.
United Airlines arrived on time 21.8 percentage points more often than Frontier Airlines on this route.
Flights on this route
Flight numbers with at least 600 operations here and still on the schedule.
| Flight | Scheduled | Operations | On time |
|---|---|---|---|
| UA787 United Airlines | 8:25 PM | 1,125 | 70.8% |
Weekly and seasonal patterns
By day of week
Tuesday is historically the most reliable day and Sunday the least, a gap of 5.7 percentage points.
By month
- Jan: 78.5%
- Feb: 85.5%
- Mar: 75.1%
- Apr: 78.1%
- May: 70.0%
- Jun: 68.7%
- Jul: 67.7%
- Aug: 75.9%
- Sep: 85.3%
- Oct: 84.3%
- Nov: 81.2%
- Dec: 79.4%
July is historically the weakest month and February the strongest, a spread of 17.8 percentage points.
Reliability over time
July 2023 – July 2026
- July 2023: 72.8% from 395 flights
- August 2023: 79.7% from 397 flights
- September 2023: 82.1% from 380 flights
- October 2023: 85.3% from 387 flights
- November 2023: 90.0% from 360 flights
- December 2023: 91.2% from 388 flights
- January 2024: 70.2% from 359 flights
- February 2024: 89.4% from 313 flights
- March 2024: 77.6% from 371 flights
- April 2024: 80.2% from 428 flights
- May 2024: 57.2% from 489 flights
- June 2024: 69.8% from 489 flights
- July 2024: 59.3% from 495 flights
- August 2024: 75.6% from 502 flights
- September 2024: 87.3% from 473 flights
- October 2024: 88.8% from 473 flights
- November 2024: 87.0% from 454 flights
- December 2024: 74.5% from 476 flights
- January 2025: 84.8% from 457 flights
- February 2025: 83.0% from 390 flights
- March 2025: 80.8% from 460 flights
- April 2025: 82.1% from 433 flights
- May 2025: 76.0% from 504 flights
- June 2025: 67.7% from 508 flights
- July 2025: 66.5% from 514 flights
- August 2025: 73.4% from 535 flights
- September 2025: 85.8% from 531 flights
- October 2025: 79.3% from 516 flights
- November 2025: 68.4% from 466 flights
- December 2025: 74.8% from 512 flights
- January 2026: 78.7% from 467 flights
- February 2026: 85.0% from 435 flights
- March 2026: 68.1% from 514 flights
- April 2026: 73.0% from 525 flights
- May 2026: 76.0% from 539 flights
- June 2026: 68.8% from 525 flights
- July 2026: 72.3% from 553 flights
Over the most recent 12 months (2025-08 to 2026-07), on-time arrivals averaged 75.2% against 79.2% in the 12 months before — declining by 4.0 percentage points.
Data and methodology
Calculated by FlyerIntel from 17,013 IAH → ORD flight records from the US DOT Bureau of Transportation Statistics, covering July 2023 – July 2026. Late means 15 or more minutes past scheduled arrival; cancelled and diverted flights are left out of on-time rates.
Full methodology · Data sources · Report a problem
Related research: How Long a Layover Needs to Be · Two Airlines on One Route · Best Time of Day to Fly From Major US Airports
Analysis last recomputed