Route reliability record
IAH→BOS
Houston to Boston
- Flights
- 2,025
- Period
- July 2025 to June 2026
- Distance
- 1,597 mi
- Carriers
- 2
This route sits in the middle of the pack with a C. About seven flights in ten arrive on time by the DOT's definition, 5 points worse than the national rate of 77.6%. The late ones land a little over an hour behind schedule. That rests on 2,025 IAH to BOS flights, of which United Airlines flew 1,565 at 75.9% on time.
Best time to fly IAH to BOS: a 5am–8am departure, ideally on a Saturday. Flights in that window arrived on time 95.0% of the time and Saturday flights 80.2%, against 72.6% for the route overall.
The national on-time rate over the same period is 77.6%, so this route runs 5 points behind the country as a whole. Across a thousand flights that is about 50 extra late arrivals.
Key figures
On time
72.6%
Arrivals under 15 minutes late, of 1,999 completed flights
Avg delay
73 min
Across delayed arrivals only, not all flights
Cancelled
1.23%
National rate is 1.81%
Best carrier
United
75.9% on time across 1,565 flights
These figures cover 2,025 flights between July 2025 and June 2026. Beyond the headline rate, 11.7% 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
Which airline is most reliable on IAH to BOS
The choice of carrier is not cosmetic here. United Airlines arrives on time 75.9% of the time; JetBlue Airways manages 61.4%. 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 | 1,565 | 75.9% | 73 min | 1.09% | B |
| JetBlue Airways | 460 | 61.4% | 73 min | 1.74% | D |
The spread between United and JetBlue is 15 points, wide enough that it should decide the booking. On a hundred trips that is 15 more arrivals inside the on-time window.
Flight by flight
Flights on IAH to BOS
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 Houston to Boston
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. IAH → BOSHouston to Boston | United Airlines | 75.1% | 75.9% | 1.09% | 5am–8am, Sat | UA 1977 07:30 |
| 2. IAH → BOSHouston to Boston | JetBlue Airways | 60.3% | 61.4% | 1.74% | 11am–2pm, Sat | B6 932 16:57 |
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 30 points, against 15 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am362 flights95.0%
- 8am–11am253 flights75.5%
- 11am–2pm564 flights66.2%
- 2pm–5pm282 flights64.9%
- 5pm–8pm561 flights67.0%
- 8pm–5am3 flights—
Scale runs 55% to 100%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 95.0% of the time, against 64.9% for the afternoon window. That is 30 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 11am–2pm window is the busiest, with 564 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 32 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.
Delays peak in October, when the on-time rate falls to 56.4%. February is the strongest month at 88.4%. Moving a flexible trip across that boundary buys 32 points. July was the busiest month here, with 216 flights.
Across the week, Saturday is the strongest day at 80.2% on time and Thursday the weakest at 67.7%. 13 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. National Airspace System accounts for 49% of the 40,000 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%National Airspace System
- 30%Late-arriving aircraft
- 16%Carrier
- 5%Extreme weather
- 0%Security
49% of delay minutes are charged to the National Airspace System: air traffic volume, runway configuration, ground stops. No carrier can price its way out of that, which is why airport choice moves the number here more than carrier choice does. That is 20,000 minutes out of 40,000, against a national NAS share of 21%. The split is drawn from 39,842 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 95.0% on time here.
Cancellations sit at 1.23% against a national 1.81%, which is ordinary. Diversions add another 0.05%.
Connections and stage length
What a delay here actually costs
For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 11.7% 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.
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 81.8% on time across 2,027 flights, 9 points above 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 2,025 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 BOS 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. February runs 88.4% on time and October 56.4%, a swing of 32 points. If the dates move at all, move them out of October before you think about anything else. 1,999 completed flights over 12 months sit behind that.
Common questions
IAH to BOS questions
How often is IAH to BOS delayed?
Roughly one flight in four arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 27.4% of the 2,025 flights in this analysis, against 22.4% nationally. Delayed flights are late by a little over an hour on average.
Which airline is most reliable on IAH to BOS?
United Airlines leads at 75.9% on time across 1,565 flights. JetBlue Airways is at the other end on 61.4%, a gap of 15 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 IAH to BOS?
The 5am–8am departure window is the strongest at 95.0% on time. The 2pm–5pm window is the weakest at 64.9%, 30 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 October delays on IAH to BOS?
October is the weakest month at 56.4% on time, compared with 88.4% in February. Across the year that is 32 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
- BOS to IAH — the return legseparate record
- George Bush Intercontinental (IAH) delay statistics
- Boston Logan International (BOS) delay statistics
- United Airlines on IAH to BOS75.9%
- JetBlue Airways on IAH to BOS61.4%
- IAH to ORD, a related route74.8%
- DCA to BOS, a related route71.4%
- IAH to DFW, a related route75.0%
- United Airlines on-time record75.9%
- JetBlue Airways on-time record61.4%
- Same route, different airline: where the carrier you pick matters most
- How often a connection fails at the major US hubs
Direction matters. IAH to BOS and BOS to IAH 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.