Route reliability record
IAH→BOS
Houston to Boston
- Flights
- 2,017
- Period
- September 2025 to August 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, 6 points worse than the national rate of 77.3%. The late ones land a little over an hour behind schedule. That rests on 2,017 IAH to BOS flights, of which United Airlines flew 1,549 at 76.1% on time.
Best time to fly IAH to BOS: a 5am–8am departure, ideally on a Saturday. Flights in that window arrived on time 94.1% of the time and Saturday flights 77.5%, against 71.5% for the route overall.
The national on-time rate over the same period is 77.3%, so this route runs 6 points behind the country as a whole. Across a thousand flights that is about 58 extra late arrivals.
Key figures
On time
71.5%
Arrivals under 15 minutes late, of 1,986 completed flights
Avg delay
78 min
Across delayed arrivals only, not all flights
Cancelled
1.49%
National rate is 1.89%
Best carrier
United
76.1% on time across 1,549 flights
These figures cover 2,017 flights between September 2025 and August 2026. Beyond the headline rate, 13.2% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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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 76.1% of the time; JetBlue Airways manages 55.9%. Sample sizes sit next to every figure, because a two-point gap across 468 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| United Airlines | 1,549 | 76.1% | 72 min | 1.10% | B |
| JetBlue Airways | 468 | 55.9% | 88 min | 2.78% | D |
The spread between United and JetBlue is 20 points, wide enough that it should decide the booking. On a hundred trips that is 20 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.
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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 | 75.3% | 76.1% | 1.10% | 5am–8am, Sat | UA 1977 07:30 |
| 2. IAH → BOSHouston to Boston | JetBlue Airways | 54.3% | 55.9% | 2.78% | 11am–2pm, Wed | B6 932 13:14 |
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 31 points, against 20 points between the best and worst carrier.
- 5am–8am361 flights94.1%
- 8am–11am253 flights75.1%
- 11am–2pm564 flights62.7%
- 2pm–5pm316 flights64.6%
- 5pm–8pm520 flights67.5%
- 8pm–5am3 flights—
Scale runs 55% to 100%. Rows with fewer than 30 flights show a dash.
The weak window here is the middle of the day, not the evening: 11am–2pm runs 62.7% on time against 94.1% for 5am–8am. That shape usually means a departure bank rather than an accumulating delay, so the recovery later in the afternoon is real rather than noise. The 11am–2pm window is the busiest, with 564 flights scheduled in it.
Explore
Filter IAH to BOS by airline, time, month and day
Pick a breakdown and a carrier. The dashed mark on each row is the same slice for every US flight.
On IAH to BOS, the best departure window is 5am–8am at 94.1% on time and the worst is 11am–2pm at 62.7%, a wide gap of 31.4 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am94.1%
- 8–11am75.1%
- 11am–2pm62.7%
- 2–5pm64.6%
- 5–8pm67.5%
- 8pm–5am—
best all US flightsScale 55% to 100%. Cells under 30 flights show a dash.
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 210 flights.
Across the week, Saturday is the strongest day at 77.5% on time and Sunday the weakest at 67.5%, a spread of 10 points.
Delay causes
Why this route gets delayed
National Airspace System accounts for 47% of the 44,000 delay minutes carriers reported here, and the remaining four split what is left.
- 47%National Airspace System
- 31%Late-arriving aircraft
- 18%Carrier
- 4%Extreme weather
- 0%Security
47% 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 21,000 minutes out of 44,000, against a national NAS share of 21%. The split is drawn from 44,076 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 94.1% on time here.
Cancellations sit at 1.49% against a national 1.89%, which is ordinary. Diversions add another 0.05%.
Connections and stage length
What a delay here actually costs
13.2% of arrivals land a full hour or more behind schedule, against 8.3% nationally. Ninety minutes is the honest minimum for a connection 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 80.1% on time across 2,018 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 2,017 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. 1,986 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 28.5% of the 2,017 flights in this analysis, against 22.7% 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 76.1% on time across 1,549 flights. JetBlue Airways is at the other end on 55.9%, a gap of 20 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 94.1% on time. The 11am–2pm window is the weakest at 62.7%, 31 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 BOS76.1%
- JetBlue Airways on IAH to BOS55.9%
- IAH to ORD, a related route75.1%
- DCA to BOS, a related route70.1%
- IAH to DFW, a related route76.4%
- United Airlines on-time record76.1%
- JetBlue Airways on-time record55.9%
- 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, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.