Flight number record

UA 2136

United Airlines · Boston to Washington

Route: BOS → IAD
Departs: 19:12
Flights: 337
Period: July 2025 to June 2026

Historical statistics for July 2025 to June 2026, not live status. For today’s UA 2136, check with United Airlines.

UA 2136 sits in the middle of the pack with a C. About seven flights in ten arrive on time by the DOT's definition, 8 points worse than the national rate of 77.6%. The late ones land a little over an hour behind schedule. That rests on 337 flights, with a median arrival 1 minute early.

The national on-time rate over the same period is 77.6%, so UA 2136 runs 8 points behind the country as a whole. Across a thousand flights that is about 84 extra late arrivals.

On time

69.2%

Arrivals under 15 minutes late, of 328 completed flights

Avg delay

78 min

Across delayed arrivals only, not all flights

Cancelled

2.37%

National rate is 1.81%

1 hour+ late

14.3%

National rate is 8.1%

These figures cover 337 flights between July 2025 and June 2026. Beyond the headline rate, 14.3% 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 2136 flies

UA 2136 flies BOS to IAD without a single fixed slot. Its most common scheduled departure was 19:12, used on 84 of 337 flights, with 19:27 (59 flights) and 19:07 (45 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.

Departs 19:1284 flights24.9%
Departs 19:2759 flights17.5%
Departs 19:0745 flights13.4%

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 19:12 departure sits in the 5pm–8pm window. Across every US flight scheduled in that window the on-time rate is 68.2%, and UA 2136 runs level with that at 69.2%. By that time of day most aircraft have flown several legs already, and whatever went wrong earlier is still in the schedule.

Against the route

UA 2136 next to BOS to IAD

Every carrier on BOS to IAD combined arrived on time 83.0% of the time across 1,464 flights, so UA 2136 is 14 points behind it. United flew 1,461 flights on the same city pair under all its flight numbers, including this one, and those ran 83.1% on time. Across its whole network United Airlines managed 79.0%, which this flight trails by 10 points.

UA 2136 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
UA 2136thin sample	337	69.2%	78 min	2.37%	C
All United Airlines on BOS–IAD	1,461	83.1%	76 min	2.05%	B
All carriers on BOS–IAD	1,464	83.0%	76 min	2.05%	B
United Airlines, whole network	821,041	79.0%	72 min	1.01%	B

Across the year

UA 2136 quarter by quarter

UA 2136 did not run the same all year. Its best quarter was Jan–Mar 2026 at 86.5% on time and its weakest Jul–Sep 2025 at 51.1%, a swing of 35 points on roughly 84 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 flights51.1%
Oct–Dec 202575 flights67.6%
Jan–Mar 202679 flights86.5%
Apr–Jun 202691 flights74.4%

Scale runs 45% to 90%. Rows with fewer than 30 flights show a dash.

By weekday, UA 2136 did best on Saturday at 91.5% on time and worst on Sunday at 55.3%. Each day rests on about 48 flights, so a gap of 36 points is worth noticing but could still narrow in another year.

Delay causes

Why UA 2136 runs late

One category carries most of the weight here. Late-arriving aircraft accounts for 68% of the 7,898 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
68%
National Airspace System
16%
Carrier
14%
Extreme weather
3%

68% 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 7,898 reported delay minutes here, that single category outweighs weather by 26 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 7,898 delay minutes reported on UA 2136.

Cancellations sit at 2.37% against a national 1.81%, which is ordinary. Diversions add another 0.30%.

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. 14.3% 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 same number turns up on four other city pairs in the data, including IAH to BOS (32), IAD to LAS (30) and SFO to BOS (23), but none flew often enough under UA 2136 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to BOS to IAD only.

One caution: this is a thin sample. 337 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 2136

For a booking, UA 2136 is a flight to put a long connection behind. 14.3% of its completed flights arrived an hour or more late, which a short layover will not absorb. If the onward flight is on a separate ticket, the risk sits with you.

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