Flight number record

UA 1977

United Airlines · Houston to Boston

Route: IAH → BOS
Departs: 07:30
Flights: 362
Period: July 2025 to June 2026

Historical statistics for July 2025 to June 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 77.6%. When something does go wrong the average delay runs a little over an hour. That rests on 362 flights, with a median arrival 10 minutes early.

Set against the rest of the country, UA 1977's record is 17 points better than the US average of 77.6%. That gap is worth roughly 174 fewer late arrivals for every thousand flights.

On time

95.0%

Arrivals under 15 minutes late, of 359 completed flights

Avg delay

69 min

Across delayed arrivals only, not all flights

Cancelled

0.83%

National rate is 1.81%

1 hour+ late

2.2%

National rate is 8.1%

These figures cover 362 flights between July 2025 and June 2026. The median arrival is 10 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.

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 177 of 362 flights, with 07:40 (73 flights) and 07:25 (53 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.

Departs 07:30177 flights48.9%
Departs 07:4073 flights20.2%
Departs 07:2553 flights14.6%

Scale runs 0% to 100%. Rows with fewer than 30 flights show a dash.

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 6 points better at 95.0%. Early departures usually start with an aircraft that has not flown yet that day, which is most of why the window does well.

Against the route

UA 1977 next to IAH to BOS

Every carrier on IAH to BOS combined arrived on time 72.6% of the time across 2,025 flights, so UA 1977 is 22 points ahead of it. United flew 1,565 flights on the same city pair under all its flight numbers, including this one, and those ran 75.9% on time. Across its whole network United Airlines managed 79.0%, which this flight beats by 16 points.

UA 1977 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
UA 1977thin sample	362	95.0%	69 min	0.83%	A+
All United Airlines on IAH–BOS	1,565	75.9%	73 min	1.09%	B
All carriers on IAH–BOS	2,025	72.6%	73 min	1.23%	C
United Airlines, whole network	821,041	79.0%	72 min	1.01%	B

Across the year

UA 1977 quarter by quarter

Quarter by quarter UA 1977 held fairly steady: 96.7% in Jul–Sep 2025, 94.5% in Oct–Dec 2025, 94.2% in Jan–Mar 2026 and 94.4% in Apr–Jun 2026. A spread of 3 points is about what a sample of this size moves on its own, so the annual figure is a fair summary.

Jul–Sep 202592 flights96.7%
Oct–Dec 202591 flights94.5%
Jan–Mar 202689 flights94.2%
Apr–Jun 202690 flights94.4%

Scale runs 85% to 100%. Rows with fewer than 30 flights show a dash.

By weekday, UA 1977 ranged from 90.2% on Saturday to 100.0% on Friday. With about 52 flights behind each day, a spread of 10 points is inside normal variation, so the day you fly is not worth changing for this flight.

Delay causes

Why UA 1977 runs late

One category carries most of the weight here. Late-arriving aircraft accounts for 45% of the 1,243 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.

Late-arriving aircraft
45%
National Airspace System
30%
Carrier
23%
Extreme weather
2%

45% 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 1,243 reported delay minutes here, that single category outweighs weather by 23 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 1,243 delay minutes reported on UA 1977.

Cancellations are rare at 0.83%, below the national 1.81% and low enough to earn the plus on the grade. Roughly one flight in 100 is called off; the risk here is arriving late, not not arriving.

Connections and routes

What a delay on this flight costs

Badly late arrivals are rare here: only 2.2% land an hour or more behind schedule, against 8.1% 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 362 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. 362 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: 95.0% on time and 0.83% cancelled. That is a base rate, not a promise about any single day.

Where to go next

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, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.

Key figures