Flight number record

UA 2647

United Airlines · San Francisco to Boston

Route: SFO → BOS
Departs: 08:25
Flights: 341
Period: July 2025 to June 2026

Historical statistics for July 2025 to June 2026, not live status. For today’s UA 2647, check with United Airlines.

UA 2647 lands a B+, 4 points better than the national rate of 77.6%. About one flight in five arrives 15 minutes late or worse, and those flights are late by an hour and a half on average. That is a workable record, not a spotless one. That rests on 341 flights, with a median arrival 10 minutes early.

On time

81.1%

Arrivals under 15 minutes late, of 339 completed flights

Avg delay

87 min

Across delayed arrivals only, not all flights

Cancelled

0.59%

National rate is 1.81%

1 hour+ late

10.6%

National rate is 8.1%

These figures cover 341 flights between July 2025 and June 2026. Beyond the headline rate, 10.6% 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 2647 flies

UA 2647 flies SFO to BOS without a single fixed slot. Its most common scheduled departure was 08:25, used on 239 of 341 flights, with 08:10 (40 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.

Departs 08:25239 flights70.1%
Departs 08:1040 flights11.7%

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 08:25 departure sits in the 8am–11am window. Across every US flight scheduled in that window the on-time rate is 84.1%, and UA 2647 runs 3 points worse at 81.1%. 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 2647 next to SFO to BOS

Every carrier on SFO to BOS combined arrived on time 76.9% of the time across 4,674 flights, so UA 2647 is 4 points ahead of it. United flew 1,866 flights on the same city pair under all its flight numbers, including this one, and those ran 79.1% on time. Across its whole network United Airlines managed 79.0%, which this flight beats by 2 points.

UA 2647 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
UA 2647thin sample	341	81.1%	87 min	0.59%	B+
All United Airlines on SFO–BOS	1,866	79.1%	73 min	1.02%	B
All carriers on SFO–BOS	4,674	76.9%	74 min	1.35%	B
United Airlines, whole network	821,041	79.0%	72 min	1.01%	B

Across the year

UA 2647 quarter by quarter

Quarter by quarter UA 2647 held fairly steady: 81.2% in Jul–Sep 2025, 77.2% in Oct–Dec 2025, 80.7% in Jan–Mar 2026 and 85.6% in Apr–Jun 2026. A spread of 8 points is about what a sample of this size moves on its own, so the annual figure is a fair summary.

Jul–Sep 202569 flights81.2%
Oct–Dec 202592 flights77.2%
Jan–Mar 202690 flights80.7%
Apr–Jun 202690 flights85.6%

Scale runs 70% to 90%. Rows with fewer than 30 flights show a dash.

By weekday, UA 2647 did best on Wednesday at 87.5% on time and worst on Thursday at 73.5%. Each day rests on about 49 flights, so a gap of 14 points is worth noticing but could still narrow in another year.

Delay causes

Why UA 2647 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 5,549 reported delay minutes.

National Airspace System
42%
Late-arriving aircraft
42%
Carrier
17%

42% 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 5,549 reported delay minutes here, that single category outweighs weather by 42 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 5,549 delay minutes reported on UA 2647.

Cancellations are rare at 0.59%, 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. 10.6% 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.

At 2,704 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 same number turns up on three other city pairs in the data, including LAX to SFO (75), ONT to SFO (37) and BOS to EWR (14), but none flew often enough under UA 2647 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to SFO to BOS only.

One caution: this is a thin sample. 341 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 2647

For a booking, read UA 2647 as 81.1% on time with 0.59% cancelled over 341 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