Carrier route record
UABOS→IAH
United Airlines · Boston to Houston
- Flights
- 1,550
- Period
- September 2025 to August 2026
- Share of route
- 77%
- Carriers
- 2
Historical statistics for September 2025 to August 2026, not live status. For today’s flights, check with United Airlines.
United on BOS to IAH lands a B, 5 points better than the national rate of 77.3%. About one flight in six arrives 15 minutes late or worse, and those flights are late by a little over an hour on average. That rests on 1,550 flights, with a median arrival 13 minutes early.
Set against the rest of the country, United's BOS to IAH record is 5 points better than the US average of 77.3%. That gap is worth roughly 50 fewer late arrivals for every thousand flights.
Key figures
On time
82.3%
Arrivals under 15 minutes late, of 1,528 completed flights
Avg delay
75 min
Across delayed arrivals only, not all flights
Cancelled
1.29%
National rate is 1.89%
Whole route
80.1%
Every carrier on BOS to IAH, 2,018 flights
These figures cover 1,550 flights between September 2025 and August 2026. The median arrival is 13 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.
Fare search by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.
Carrier by carrier
United against every carrier on BOS to IAH
United flew 1,550 of the 2,018 flights on BOS to IAH, most of the route. Its 82.3% on time is 2 points better than the route as a whole, which runs 80.1%. Ranked by on-time rate it is first of two carriers on the route, where the range runs from United at 82.3% to JetBlue at 72.7%.
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 (this page) | 1,550 | 82.3% | 75 min | 1.29% | B |
| JetBlue Airways | 468 | 72.7% | 58 min | 2.99% | C |
Flight by flight
United flight numbers on BOS to IAH
Timetable by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.
Departure window
When United runs best on this route
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 29 points, against half a point between the best and worst carrier.
- 5am–8am441 flights93.1%
- 8am–11am165 flights91.9%
- 11am–2pm338 flights87.1%
- 2pm–5pm354 flights73.4%
- 5pm–8pm252 flights63.6%
- 8pm–5am—
Scale runs 55% to 100%. Rows with fewer than 30 flights show a dash.
The 5pm–8pm window is where this operation falls apart: 63.6% on time, against 93.1% 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 5am–8am window is the busiest, with 441 flights scheduled in it.
Across the year
United on BOS to IAH through the year
Delays peak in May, when the on-time rate falls to 72.1%. February is the strongest month at 92.1%. Moving a flexible trip across that boundary buys 20 points. October was the busiest month here, with 153 flights.
Across the week, Wednesday is the strongest day at 87.5% on time and Thursday the weakest at 79.2%, a spread of 8 points.
Arrival by arrival
How late United on BOS to IAH runs when it is late
United on BOS to IAH often beats the schedule: 735 of 1,528 completed flights, 48%, arrived 15 minutes or more early. The 270 late arrivals split 87 under half an hour, 81 between 30 and 60 minutes, and 102 an hour or more.
- 15+ min early735 flights48.1%
- Within 15 min523 flights34.2%
- 15–29 min late87 flights5.7%
- 30–59 min late81 flights5.3%
- 1–2 hours late62 flights4.1%
- 2+ hours late40 flights2.6%
Scale runs 0% to 100%.
Share of 1,528 completed flights by arrival against schedule.
67 of 248 late departures made up the time and arrived on time, 27% of them. In the other direction, 89 flights left on time yet arrived 15 minutes late or more, so that delay built up after pushback: in the air, in a holding pattern or on the ground at IAH.
The worst days
Worst days for United on BOS to IAH
The latest arrival of the period was on 7 August 2026, 9 hours 34 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). On three of the five worst days the largest share was filed as a late-arriving aircraft.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 7 August 2026 | 9 hours 34 minutes | Carrier |
| 29 January 2026 | 8 hours 30 minutes | Late-arriving aircraft |
| 18 July 2026 | 7 hours 24 minutes | Carrier |
| 7 June 2026 | 7 hours 6 minutes | Late-arriving aircraft |
| 6 June 2026 | 6 hours 57 minutes | Late-arriving aircraft |
Delay causes
Why United runs late on this route
Late-arriving aircraft accounts for 50% of the 20,000 delay minutes carriers reported here, and the remaining four split what is left.
- 50%Late-arriving aircraft
- 26%National Airspace System
- 23%Carrier
- 2%Extreme weather
50% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 20,000 reported delay minutes here, that single category outweighs weather by 33 to one. The split is drawn from 20,138 reported delay minutes.
The practical consequence: the 5am–8am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 93.1% on time here.
Cancellations sit at 1.29% against a national 1.89%, which is ordinary. Diversions add another 0.13%.
Connections and stage length
What a delay here costs
6.7% 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.
At 1,597 miles this is transcontinental flying, and long routes get a quiet structural advantage. Scheduled block time on a flight this length carries more padding in absolute minutes, so a twenty-minute late departure often still becomes an on-time arrival. Read the on-time rate here as slightly flattering next to a short-haul route with the same operational quality.
The return leg is a different operation and performs like one: it runs 76.1% on time across 1,549 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.
The sample behind these figures is 1,550 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.
What to do with this
Booking United on BOS to IAH
Put together: the calendar is the biggest lever here, not the carrier or the hour. February runs 92.1% on time and May 72.1%, a swing of 20 points. If the dates move at all, move them out of May before you think about anything else. 1,528 completed flights over 12 months sit behind that.
Related
Where to go next
- BOS to IAH, every carrier
- United on IAH to BOS, the return leg
- JetBlue Airways on BOS to IAH72.7%
- United Airlines network-wide record
- Boston Logan International (BOS) delay statistics
- George Bush Intercontinental (IAH) delay statistics
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.05 million flight records
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.