Airport month record
IAHJUL
George Bush Intercontinental in July 2025
- Departures
- 10,311
- Month
- July 2025
- National, same month
- 71.1%
- Carriers
- 9
Historical statistics for July 2025, not live status or a forecast for this year’s July. For today’s conditions at IAH, see live FAA status.
IAH in July sits in the middle of the pack with a C. About seven flights in ten arrive on time by the DOT's definition, 2 points worse than the national rate of 71.1%. The late ones land an hour and a half behind schedule. That rests on 10,311 flights, of which Delta Air Lines flew 717 at 75.7% on time.
Delta Air Lines is the most reliable of the five carriers covered here at 75.7% on time across 717 flights.
Key figures
On time
68.8%
Arrivals under 15 minutes late, of 10,071 completed departures
Avg delay
88 min
Across delayed arrivals only, not all flights
Cancelled
1.74%
Nationally in July: 2.45%
Whole year
78.4%
IAH across all twelve months
These figures cover 10,311 departures from George Bush Intercontinental in July 2025. On time means an arrival less than 15 minutes after the scheduled gate time, the DOT's threshold, and the national comparison uses every US departure in the same month rather than the whole year.
Against the year
July next to IAH's other months
Against IAH's own year, July ran 10 points worse than the twelve-month rate of 78.4%, which makes it the worst of the twelve months in the data. Cancellations are where July stands out: 1.74% of scheduled departures were called off, 1.5 times the airport's rate across the year.
| Month | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| July 2025 (this page) | 10,311 | 68.8% | 88 min | 1.74% | C |
| August 2025 | 9,889 | 74.1% | 74 min | 0.87% | C+ |
| September 2025 | 9,493 | 85.6% | 69 min | 0.20% | A+ |
| October 2025 | 10,247 | 80.7% | 65 min | 0.30% | B+ |
| November 2025 | 10,022 | 78.2% | 73 min | 1.06% | B |
| December 2025 | 9,971 | 79.4% | 71 min | 0.60% | B+ |
| January 2026 | 9,656 | 85.7% | 74 min | 3.07% | A− |
| February 2026 | 8,976 | 85.6% | 68 min | 1.06% | A |
| March 2026 | 10,492 | 76.4% | 95 min | 2.89% | B |
| April 2026 | 10,022 | 80.4% | 69 min | 0.57% | B+ |
| May 2026 | 10,105 | 77.1% | 73 min | 0.46% | B+ |
| June 2026 | 9,903 | 69.9% | 79 min | 0.75% | C+ |
Departure window
The best time of day to leave IAH in July
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 33 points, against 9 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am1,716 flights86.8%
- 8am–11am1,389 flights83.0%
- 11am–2pm1,551 flights69.5%
- 2pm–5pm1,807 flights62.6%
- 5pm–8pm1,976 flights54.0%
- 8pm–5am1,872 flights62.3%
Scale runs 45% to 90%. Rows with fewer than 30 flights show a dash.
The 5pm–8pm window is where this operation falls apart: 54.0% on time, against 86.8% for the 5am–8am slot. By evening the aircraft flying these rotations have absorbed a full day of small delays and there is no slack left to recover in. The 5pm–8pm window is the busiest, with 1,976 flights scheduled in it.
Across the week, Saturday is the strongest day at 77.7% on time and Sunday the weakest at 64.3%. 13 points is a smaller lever than departure hour, but it is free.
Carrier by carrier
Which airlines ran best at IAH in July
The choice of carrier is not cosmetic here. Delta Air Lines arrives on time 75.7% of the time; American Airlines manages 66.7%. Sample sizes sit next to every figure, because a two-point gap across 681 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| United Airlines | 6,013 | 67.4% | 82 min | 1.43% | C |
| SkyWest Airlines | 1,551 | 70.7% | 101 min | 1.74% | C |
| Delta Air Lines | 717 | 75.7% | 81 min | 1.12% | B |
| American Airlines | 681 | 66.7% | 131 min | 3.82% | C− |
| Spirit Airlines | 666 | 73.4% | 84 min | 2.25% | C |
| Frontier Airlinesthin sample | 320 | 62.7% | 84 min | 0.94% | D+ |
| Envoy Airthin sample | 159 | 75.3% | 82 min | 5.03% | B− |
| Alaska Airlinesthin sample | 123 | 75.0% | 59 min | 1.63% | B |
| JetBlue Airwaysthin sample | 62 | 57.6% | 67 min | 4.84% | D− |
American Airlines cancels 3.8% 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.
Route by route
Busiest routes out of IAH in July
| Route | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| IAH to ORD · Chicago | 514 | 66.5% | 93 min | 1.56% | C |
| IAH to DFW · Dallas-Fort Worth | 457 | 68.7% | 103 min | 4.60% | C− |
| IAH to LAX · Los Angeles | 454 | 78.2% | 79 min | 1.10% | B |
| IAH to ATL · Atlanta | 413 | 71.9% | 74 min | 1.45% | C |
| IAH to DEN · Denver | 402 | 72.5% | 82 min | 0.00% | C+ |
| IAH to LGA · New York | 380 | 64.2% | 82 min | 2.89% | D |
| IAH to EWR · Newarkthin sample | 341 | 63.2% | 91 min | 4.99% | D− |
| IAH to MIA · Miamithin sample | 312 | 66.2% | 69 min | 2.56% | C |
| IAH to MCO · Orlandothin sample | 304 | 64.7% | 86 min | 0.99% | D+ |
| IAH to SFO · San Franciscothin sample | 299 | 73.9% | 85 min | 0.00% | C+ |
| IAH to LAS · Las Vegasthin sample | 291 | 75.4% | 74 min | 0.69% | B+ |
| IAH to MSY · New Orleansthin sample | 242 | 67.6% | 74 min | 1.65% | C |
| IAH to SEA · Seattlethin sample | 236 | 67.1% | 64 min | 1.69% | C |
| IAH to CLT · Charlottethin sample | 222 | 64.2% | 93 min | 3.15% | D− |
| IAH to BOS · Bostonthin sample | 216 | 70.3% | 93 min | 1.85% | C |
| IAH to PHX · Phoenixthin sample | 215 | 70.3% | 101 min | 1.40% | C |
| IAH to DCA · Washingtonthin sample | 207 | 58.6% | 86 min | 2.42% | D |
| IAH to OKC · Oklahoma Citythin sample | 206 | 72.9% | 87 min | 0.97% | C+ |
| IAH to DTW · Detroitthin sample | 198 | 75.6% | 122 min | 1.52% | B |
| IAH to FLL · Fort Lauderdalethin sample | 194 | 69.6% | 71 min | 1.03% | C |
| IAH to AUS · Austinthin sample | 188 | 65.2% | 85 min | 0.53% | C+ |
| IAH to SAT · San Antoniothin sample | 185 | 71.6% | 97 min | 1.08% | C |
| IAH to TPA · Tampathin sample | 173 | 69.4% | 100 min | 0.00% | C+ |
| IAH to MAF · Midlandthin sample | 160 | 71.0% | 92 min | 2.50% | C |
| IAH to IAD · Washingtonthin sample | 155 | 57.8% | 68 min | 0.65% | D+ |
Delay causes
What held IAH up in July
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 277,000 reported delay minutes.
- 41%Late-arriving aircraft
- 30%Carrier
- 18%National Airspace System
- 12%Extreme weather
- 0%Security
Extreme weather accounts for 12% of delay minutes, well above the single-digit share typical across the system. Weather delays are lumpy: they arrive as whole bad days rather than as a steady drag, so the comparison with the other months below is the more useful view of the risk. The national share is 7%, so this operation carries roughly 1.6 times the usual weather exposure. The split is drawn from 276,765 reported delay minutes.
Cancellations sit at 1.74% against a national 2.45%, which is ordinary. Diversions add another 0.59%.
For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 14.5% of arrivals land a full hour or more behind schedule, against 12.1% 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.
What to do with this
Flying from IAH in July
For a July trip through IAH: plan on this being one of the airport's harder months. The 5am–8am departures held up best at 86.8% on time, and with 14.5% of arrivals an hour or more late, a connection here deserves more slack than the same trip in January would.
Related
Where to go next
- George Bush Intercontinental (IAH), the whole year
- IAH in August74.1%
- IAH in September85.6%
- IAH in October80.7%
- IAH in November78.2%
- IAH in December79.4%
- IAH in January85.7%
- IAH in February85.6%
- IAH in March76.4%
- IAH in April80.4%
- IAH in May77.1%
- IAH in June69.9%
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.