Flight number record

UA 1577

United Airlines · Chicago to San Francisco

Route: ORD → SFO
Departs: 14:40
Flights: 363
Period: July 2025 to June 2026

Historical statistics for July 2025 to June 2026, not live status. For today’s UA 1577, check with United Airlines.

UA 1577 sits in the middle of the pack with a C. Close to three flights in four arrive on time by the DOT's definition, 4 points worse than the national rate of 77.6%. The late ones land close to two hours behind schedule. That rests on 363 flights, with a median arrival 2 minutes early.

The national on-time rate over the same period is 77.6%, so UA 1577 runs 4 points behind the country as a whole. Across a thousand flights that is about 42 extra late arrivals.

On time

73.4%

Arrivals under 15 minutes late, of 357 completed flights

Avg delay

105 min

Across delayed arrivals only, not all flights

Cancelled

1.65%

National rate is 1.81%

1 hour+ late

13.4%

National rate is 8.1%

These figures cover 363 flights between July 2025 and June 2026. Beyond the headline rate, 13.4% 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 1577 flies

UA 1577 flies ORD to SFO without a single fixed slot. Its most common scheduled departure was 14:40, used on 106 of 363 flights, with 14:35 (103 flights) and 14:15 (51 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.

Departs 14:40106 flights29.2%
Departs 14:35103 flights28.4%
Departs 14:1551 flights14.0%

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 14:40 departure sits in the 2pm–5pm window. Across every US flight scheduled in that window the on-time rate is 72.4%, and UA 1577 runs level with that at 73.4%. Midday slots inherit some of the morning's delays without yet carrying the full weight of the evening's.

Against the route

UA 1577 next to ORD to SFO

Every carrier on ORD to SFO combined arrived on time 67.6% of the time across 5,627 flights, so UA 1577 is 6 points ahead of it. United flew 3,813 flights on the same city pair under all its flight numbers, including this one, and those ran 69.8% on time. Across its whole network United Airlines managed 79.0%, which this flight trails by 6 points.

UA 1577 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
UA 1577thin sample	363	73.4%	105 min	1.65%	C
All United Airlines on ORD–SFO	3,813	69.8%	73 min	1.05%	C
All carriers on ORD–SFO	5,627	67.6%	73 min	1.32%	C
United Airlines, whole network	821,041	79.0%	72 min	1.01%	B

Across the year

UA 1577 quarter by quarter

UA 1577 did not run the same all year. Its best quarter was Jan–Mar 2026 at 83.3% on time and its weakest Apr–Jun 2026 at 64.4%, a swing of 19 points on roughly 91 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 flights72.1%
Oct–Dec 202591 flights73.6%
Jan–Mar 202690 flights83.3%
Apr–Jun 202690 flights64.4%

Scale runs 55% to 90%. Rows with fewer than 30 flights show a dash.

By weekday, UA 1577 did best on Tuesday at 79.2% on time and worst on Sunday at 64.0%. Each day rests on about 52 flights, so a gap of 15 points is worth noticing but could still narrow in another year.

Delay causes

Why UA 1577 runs late

One category carries most of the weight here. Late-arriving aircraft accounts for 43% of the 9,947 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
43%
Carrier
27%
National Airspace System
25%
Extreme weather
4%

43% 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 9,947 reported delay minutes here, that single category outweighs weather by 11 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 9,947 delay minutes reported on UA 1577.

Cancellations sit at 1.65% against a national 1.81%, which is ordinary. Diversions add another 0.00%.

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. 13.4% 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 1,846 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 nine other city pairs in the data, including SFO to SAN (135), SFO to SEA (71) and ATL to ORD (35), but none flew often enough under UA 1577 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to ORD to SFO only.

One caution: this is a thin sample. 363 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 1577

For a booking, UA 1577 is a flight to put a long connection behind. 13.4% 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