Flight number record

UA 1788

United Airlines · Houston to Washington

Route: IAH → IAD
Departs: 16:45
Flights: 324
Period: July 2025 to June 2026

Historical statistics for July 2025 to June 2026, not live status. For today’s UA 1788, check with United Airlines.

UA 1788 lands a B+, level with 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 324 flights, with a median arrival 3 minutes early.

On time

78.0%

Arrivals under 15 minutes late, of 323 completed flights

Avg delay

67 min

Across delayed arrivals only, not all flights

Cancelled

0.31%

National rate is 1.81%

1 hour+ late

9.3%

National rate is 8.1%

These figures cover 324 flights between July 2025 and June 2026. Beyond the headline rate, 9.3% 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.

Schedule

When UA 1788 flies

UA 1788 flies IAH to IAD without a single fixed slot. Its most common scheduled departure was 16:45, used on 97 of 324 flights, with 16:50 (81 flights) and 16:40 (44 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.

Departs 16:4597 flights29.9%
Departs 16:5081 flights25.0%
Departs 16:4044 flights13.6%

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 16:45 departure sits in the 2pm–5pm window. Across every US flight scheduled in that window the on-time rate is 72.4%, and UA 1788 runs 6 points better at 78.0%. Midday slots inherit some of the morning's delays without yet carrying the full weight of the evening's.

Against the route

UA 1788 next to IAH to IAD

Every carrier on IAH to IAD combined arrived on time 80.4% of the time across 1,867 flights, so UA 1788 is 2 points behind it. Across its whole network United Airlines managed 79.0%, close to this flight's figure.

UA 1788 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
UA 1788thin sample	324	78.0%	67 min	0.31%	B+
All United Airlines on IAH–IAD	1,867	80.4%	59 min	0.43%	B+
All carriers on IAH–IAD	1,867	80.4%	59 min	0.43%	B+
United Airlines, whole network	821,041	79.0%	72 min	1.01%	B

Across the year

UA 1788 quarter by quarter

UA 1788 did not run the same all year. Its best quarter was Oct–Dec 2025 at 84.8% on time and its weakest Jul–Sep 2025 at 68.5%, a swing of 16 points on roughly 81 flights a quarter. The twelve-month rate averages over that, so if you are flying in a weak quarter the quarter's own figure is the better guide.

Jul–Sep 202592 flights68.5%
Oct–Dec 202592 flights84.8%
Jan–Mar 202690 flights78.7%
Apr–Jun 202650 flights82.0%

Scale runs 60% to 90%. Rows with fewer than 30 flights show a dash.

By weekday, UA 1788 did best on Monday at 87.0% on time and worst on Friday at 71.7%. Each day rests on about 46 flights, so a gap of 15 points is worth noticing but could still narrow in another year.

Delay causes

Why UA 1788 runs late

Carriers report a reason for every delay minute they cause, in five DOT categories. The split below is by minutes, not by number of flights, so a handful of very long weather delays weighs as much as many short ones. It covers 4,766 reported delay minutes.

Carrier
35%
Late-arriving aircraft
33%
National Airspace System
23%
Extreme weather
9%

The largest share of delay minutes, 35%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. Unlike weather, that is a management outcome, and it is the category where the gap between two carriers on the same schedule is genuinely earned. It accounts for 1,658 of the 4,766 delay minutes reported here. The split is drawn from 4,766 delay minutes reported on UA 1788.

Cancellations are rare at 0.31%, 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

For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 9.3% 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.

The 1,190 miles between these two airports put this in the middle of the US network, around two and a half to three hours of block time. That is enough cruise to absorb a ten-minute late pushback and not enough to absorb thirty. It is also long enough that the aircraft usually flies three or four legs a day rather than six, which slows how fast delay compounds.

The same number turns up on two other city pairs in the data, including SFO to IAH (168) and GJT to DEN (41), but none flew often enough under UA 1788 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to IAH to IAD only.

One caution: this is a thin sample. 324 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 1788

For a booking, read UA 1788 as 78.0% on time with 0.31% cancelled over 324 flights. Those are rates from the past twelve months, not a forecast for any particular 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