Flight number record
UA 1977
United Airlines · Houston to Boston
- Route
- IAH → BOS
- Departs
- 07:30
- Flights
- 361
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s UA 1977, check with United Airlines.
UA 1977 earns an A. Nearly every flight arrives inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 17 points better than the national rate of 77.3%. When something does go wrong the average delay runs about an hour. That rests on 361 flights, with a median arrival 11 minutes early.
Set against the rest of the country, UA 1977's record is 17 points better than the US average of 77.3%. That gap is worth roughly 168 fewer late arrivals for every thousand flights.
Key figures
On time
94.1%
Arrivals under 15 minutes late, of 357 completed flights
Avg delay
60 min
Across delayed arrivals only, not all flights
Cancelled
1.11%
National rate is 1.89%
1 hour+ late
2.0%
National rate is 8.3%
These figures cover 361 flights between September 2025 and August 2026. The median arrival is 11 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.
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Schedule
When UA 1977 flies
UA 1977 flies IAH to BOS without a single fixed slot. Its most common scheduled departure was 07:30, used on 168 of 361 flights, with 07:20 (63 flights) and 07:40 (60 flights) next.
- Departs 07:30168 flights46.5%
- Departs 07:2063 flights17.5%
- Departs 07:4060 flights16.6%
Scale runs 0% to 100%.
Share of scheduled departures at each local time. Times used on fewer than one flight in ten are not listed.
A 07:30 departure sits in the 5am–8am window. Across every US flight scheduled in that window the on-time rate is 89.3%, and UA 1977 runs 5 points better at 94.1%. Early departures usually start with an aircraft that has not flown yet that day, which is most of why the window does well.
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Against the route
UA 1977 next to IAH to BOS
Every carrier on IAH to BOS combined arrived on time 71.5% of the time across 2,017 flights, so UA 1977 is 23 points ahead of it. United flew 1,549 flights on the same city pair under all its flight numbers, including this one, and those ran 76.1% on time. Across its whole network United Airlines managed 78.8%, which this flight beats by 15 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| UA 1977thin sample | 361 | 94.1% | 60 min | 1.11% | A |
| All United Airlines on IAH–BOS | 1,549 | 76.1% | 72 min | 1.10% | B |
| All carriers on IAH–BOS | 2,017 | 71.5% | 78 min | 1.49% | C |
| United Airlines, whole network | 830,825 | 78.8% | 73 min | 1.02% | B |
Across the year
UA 1977 quarter by quarter
Quarter by quarter UA 1977 held fairly steady: 93.3% in Jul–Sep 2025, 94.5% in Oct–Dec 2025, 94.2% in Jan–Mar 2026, 94.4% in Apr–Jun 2026 and 93.3% in Jul–Sep 2026. A spread of about a point is about what a sample of this size moves on its own, so the annual figure is a fair summary.
- Jul–Sep 202530 flights93.3%
- Oct–Dec 202591 flights94.5%
- Jan–Mar 202689 flights94.2%
- Apr–Jun 202690 flights94.4%
- Jul–Sep 202661 flights93.3%
Scale runs 85% to 100%.
By weekday, UA 1977 did best on Sunday at 98.1% on time and worst on Saturday at 86.0%. Each day rests on about 52 flights, so a gap of 12 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late UA 1977 runs when it is late
UA 1977 often beats the schedule: 135 of 357 completed flights, 38%, arrived 15 minutes or more early. The 21 late arrivals split 10 under half an hour, 4 between 30 and 60 minutes, and 7 an hour or more.
- 15+ min early135 flights37.8%
- Within 15 min201 flights56.3%
- 15–29 min late10 flights2.8%
- 30–59 min late4 flights1.1%
- 1–2 hours late4 flights1.1%
- 2+ hours late3 flights0.8%
Scale runs 0% to 100%.
Share of 357 completed flights by arrival against schedule.
A late pushback is often recovered here: of 27 departures that left 15 minutes late or more, 13 still arrived on time. Only 7 left on time and still arrived late.
The worst days
Worst days for UA 1977
The latest arrival of the period was on 30 April 2026, 4 hours 18 minutes behind schedule; most of its delay minutes were filed as a late-arriving aircraft. The same cause led on three of the five worst days.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 30 April 2026 | 4 hours 18 minutes | Late-arriving aircraft |
| 18 May 2026 | 2 hours 40 minutes | Late-arriving aircraft |
| 24 December 2025 | 2 hours 5 minutes | Late-arriving aircraft |
| 25 September 2025 | 1 hour 56 minutes | National Airspace System |
| 18 September 2025 | 1 hour 46 minutes | National Airspace System |
Delay causes
Why UA 1977 runs late
Late-arriving aircraft accounts for 47% of the 1,264 delay minutes carriers reported here, and the remaining four split what is left.
- 47%Late-arriving aircraft
- 34%National Airspace System
- 17%Carrier
- 2%Extreme weather
47% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 1,264 reported delay minutes here, that single category outweighs weather by 25 to one. The split is drawn from 1,264 delay minutes reported on UA 1977.
Cancellations sit at 1.11% against a national 1.89%, which is ordinary. Diversions add another 0.00%.
Connections and routes
What a delay on this flight costs
Badly late arrivals are rare here: only 2.0% land an hour or more behind schedule, against 8.3% nationally. Connections built on this flight are about as safe as US domestic connections get, though a cancelled flight still ignores every layover you give it.
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.
Every one of the 361 flights under UA 1977 in the data flew IAH to BOS. The number was not reused on any other city pair, which makes this a clean record of one route.
One caution: this is a thin sample. 361 flights over twelve months is enough to clear this site's floor but not enough to pin the rate down tightly, and a single bad week moves it by more than a point. Treat the grade as a rough reading.
What to do with this
Booking UA 1977
For a booking, UA 1977 has one of the better records a US domestic flight can show: 94.1% on time and 1.11% cancelled. That is a base rate, not a promise about any single day.
Related
Where to go next
- IAH to BOS, every carrier and departure
- BOS to IAH, the return direction
- JetBlue Airways 932 on the same route58.1%
- George Bush Intercontinental (IAH) delay statistics
- Boston Logan International (BOS) delay statistics
- United Airlines on-time record
- Every United Airlines flight number with a record
- The most and least reliable flight numbers in the US
- Why the first flight of the morning is statistically safest
A flight number here means United Airlines’s own number as it reports to the DOT. How the figures are computed is on the methodology page.
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.