Route reliability record
BOS→IAH
Boston to Houston
- Flights
- 2,027
- Period
- July 2025 to June 2026
- Distance
- 1,597 mi
- Carriers
- 2
This route lands a B, 4 points better than the national rate of 77.6%. Roughly one flight in five arrives 15 minutes late or worse, and those flights are late by about an hour on average. That is a workable record, not a spotless one. That rests on 2,027 BOS to IAH flights, of which United Airlines flew 1,567 at 83.8% on time.
Best time to fly BOS to IAH: a 5am–8am departure, ideally on a Wednesday. Flights in that window arrived on time 93.0% of the time and Wednesday flights 85.8%, against 81.8% for the route overall.
Set against the rest of the country, this route's record is 4 points better than the US average of 77.6%. That gap is worth roughly 42 fewer late arrivals for every thousand flights.
Key figures
On time
81.8%
Arrivals under 15 minutes late, of 1,992 completed flights
Avg delay
67 min
Across delayed arrivals only, not all flights
Cancelled
1.43%
National rate is 1.81%
Best carrier
United
83.8% on time across 1,567 flights
These figures cover 2,027 flights between July 2025 and June 2026. The median arrival is 12 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.
Carrier by carrier
Which airline is most reliable on BOS to IAH
The choice of carrier is not cosmetic here. United Airlines arrives on time 83.8% of the time; JetBlue Airways manages 75.1%. Sample sizes sit next to every figure, because a two-point gap across 460 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| United Airlines | 1,567 | 83.8% | 71 min | 1.47% | B |
| JetBlue Airways | 460 | 75.1% | 56 min | 1.30% | B |
United leads JetBlue by 9 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.
Flight by flight
Flights on BOS to IAH
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.
Best ways to make this trip
The most reliable ways to fly Boston to Houston
Every airline on this route, ranked by how often a scheduled flight actually operated and arrived on time, with its best departure time and most punctual flight number. No nearby airport pair beat these.
| Option | Airline | Success | On time | Cancelled | Best departure | Most punctual flight |
|---|---|---|---|---|---|---|
| 1. BOS → IAHBoston to Houston | United Airlines | 82.6% | 83.8% | 1.47% | 5am–8am, Mon | UA 226 07:25 |
| 2. BOS → IAHBoston to Houston | JetBlue Airways | 74.1% | 75.1% | 1.30% | 8am–11am, Wed | B6 2033 12:48 |
Success is the share of scheduled flights that operated and arrived less than 15 minutes late, so a cancelled flight counts against it. “(route)” means the best time comes from every carrier on the route rather than this airline alone.
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 26 points, against 9 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am494 flights93.0%
- 8am–11am455 flights85.2%
- 11am–2pm403 flights82.3%
- 2pm–5pm422 flights73.9%
- 5pm–8pm253 flights66.7%
- 8pm–5am—
Scale runs 60% to 100%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 93.0% of the time, against 66.7% for the evening window. That is 26 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 5am–8am window is the busiest, with 494 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 19 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.
April is the best month on the calendar at 91.4% on time. Shoulder season thins the schedule and takes the summer weather with it, and the operation gets its margin back. July was the busiest month here, with 216 flights.
Across the week, Wednesday is the strongest day at 85.8% on time and Thursday the weakest at 77.1%. 9 points is a smaller lever than departure hour, but it is free.
Delay causes
Why this route gets delayed
One category carries most of the weight here. Late-arriving aircraft accounts for 49% of the 24,000 delay minutes carriers reported, and the remaining four split what is left. The split is by minutes rather than by flights, so a few very long delays count for as much as many short ones.
- 49%Late-arriving aircraft
- 29%National Airspace System
- 21%Carrier
- 1%Extreme weather
- 0%Security
49% 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 24,000 reported delay minutes here, that single category outweighs weather by 49 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 24,160 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 93.0% on time here.
Cancellations sit at 1.43% against a national 1.81%, which is ordinary. Diversions add another 0.30%.
Connections and stage length
What a delay here actually costs
6.0% of arrivals land an hour or more late, close to the national 8.1%. That is the figure that decides a connection, and it says a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last about 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 72.6% on time across 2,025 flights, 9 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 9 points of difference.
The sample behind these figures is 2,027 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 IAH 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. April runs 91.4% on time and May 72.5%, a swing of 19 points. If the dates move at all, move them out of May before you think about anything else. 1,992 completed flights over 12 months sit behind that.
Common questions
BOS to IAH questions
How often is BOS to IAH delayed?
Roughly 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 18.2% of the 2,027 flights in this analysis, against 22.4% nationally. Delayed flights are late by about an hour on average.
Which airline is most reliable on BOS to IAH?
United Airlines leads at 83.8% on time across 1,567 flights. JetBlue Airways is at the other end on 75.1%, a gap of 9 points. Sample size matters as much as the percentage: a rate built from a few hundred flights moves around far more than one built from ten thousand.
What time of day has the fewest delays on BOS to IAH?
The 5am–8am departure window is the strongest at 93.0% on time. The 5pm–8pm window is the weakest at 66.7%, 26 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 May delays on BOS to IAH?
May is the weakest month at 72.5% on time, compared with 91.4% in April. Across the year that is 19 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
- IAH to BOS — the return legseparate record
- Boston Logan International (BOS) delay statistics
- George Bush Intercontinental (IAH) delay statistics
- United Airlines on BOS to IAH83.8%
- JetBlue Airways on BOS to IAH75.1%
- BOS to DCA, a related route74.0%
- ORD to IAH, a related route75.0%
- BOS to ORD, a related route72.7%
- United Airlines on-time record83.8%
- JetBlue Airways on-time record75.1%
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.04 million flight records
Direction matters. BOS to IAH and IAH to BOS 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, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.