Flight number record
UA 1577
United Airlines · Chicago to San Francisco
- Route
- ORD → SFO
- Departs
- 14:35
- Flights
- 357
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 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+. About seven flights in ten arrive on time by the DOT's definition, 5 points worse than the national rate of 77.3%. The late ones land close to two hours behind schedule. That rests on 357 flights, with a median arrival 1 minute early.
The national on-time rate over the same period is 77.3%, so UA 1577 runs 5 points behind the country as a whole. Across a thousand flights that is about 48 extra late arrivals.
Key figures
On time
72.5%
Arrivals under 15 minutes late, of 357 completed flights
Avg delay
105 min
Across delayed arrivals only, not all flights
Cancelled
0.00%
National rate is 1.89%
1 hour+ late
13.7%
National rate is 8.3%
These figures cover 357 flights between September 2025 and August 2026. Beyond the headline rate, 13.7% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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Schedule
When UA 1577 flies
UA 1577 flies ORD to SFO without a single fixed slot. Its most common scheduled departure was 14:35, used on 124 of 357 flights, with 14:30 (64 flights) and 14:40 (57 flights) next.
- Departs 14:35124 flights34.7%
- Departs 14:3064 flights17.9%
- Departs 14:4057 flights16.0%
Scale runs 0% to 100%.
Share of scheduled departures at each local time. Times used on fewer than one flight in ten are not listed.
A 14:35 departure sits in the 2pm–5pm window. Across every US flight scheduled in that window the on-time rate is 71.9%, and UA 1577 runs level with that at 72.5%. Midday slots inherit some of the morning's delays without yet carrying the full weight of the evening's.
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Against the route
UA 1577 next to ORD to SFO
Every carrier on ORD to SFO combined arrived on time 66.2% of the time across 5,649 flights, so UA 1577 is 6 points ahead of it. United flew 3,883 flights on the same city pair under all its flight numbers, including this one, and those ran 69.1% on time. Across its whole network United Airlines managed 78.8%, which this flight trails by 6 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| UA 1577thin sample | 357 | 72.5% | 105 min | 0.00% | C+ |
| All United Airlines on ORD–SFO | 3,883 | 69.1% | 75 min | 0.82% | C+ |
| All carriers on ORD–SFO | 5,649 | 66.2% | 74 min | 1.08% | C |
| United Airlines, whole network | 830,825 | 78.8% | 73 min | 1.02% | 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 71 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 202530 flights70.0%
- Oct–Dec 202591 flights73.6%
- Jan–Mar 202690 flights83.3%
- Apr–Jun 202690 flights64.4%
- Jul–Sep 202656 flights67.9%
Scale runs 55% to 90%.
By weekday, UA 1577 did best on Tuesday at 82.7% on time and worst on Friday at 61.5%. Each day rests on about 51 flights, so a gap of 21 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late UA 1577 runs when it is late
The 98 late arrivals split 31 under half an hour, 18 between 30 and 60 minutes, and 49 an hour or more.
- 15+ min early76 flights21.3%
- Within 15 min183 flights51.3%
- 15–29 min late31 flights8.7%
- 30–59 min late18 flights5.0%
- 1–2 hours late20 flights5.6%
- 2+ hours late29 flights8.1%
Scale runs 0% to 100%.
Share of 357 completed flights by arrival against schedule.
22 of 100 late departures made up the time and arrived on time, 22% of them. In the other direction, 20 flights left on time yet arrived 15 minutes late or more, so that delay built up after pushback: in the air, in a holding pattern or on the ground at SFO.
The worst days
Worst days for UA 1577
The latest arrival of the period was on 4 June 2026, 16 hours 2 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). On three of the five worst days the largest share was filed as a late-arriving aircraft.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 4 June 2026 | 16 hours 2 minutes | Carrier |
| 29 November 2025 | 8 hours 15 minutes | Late-arriving aircraft |
| 27 July 2026 | 7 hours 39 minutes | Carrier |
| 18 September 2025 | 7 hours 16 minutes | Late-arriving aircraft |
| 11 June 2026 | 6 hours 30 minutes | Late-arriving aircraft |
Delay causes
Why UA 1577 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 10,000 reported delay minutes.
- 37%Late-arriving aircraft
- 33%Carrier
- 25%National Airspace System
- 5%Extreme weather
37% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 10,000 reported delay minutes here, that single category outweighs weather by 8 to one. The split is drawn from 10,241 delay minutes reported on UA 1577.
Cancellations are rare at 0.00%, below the national 1.89% and low enough to earn the plus on the grade. Almost no flights are called off; the risk here is arriving late, not not arriving.
Connections and routes
What a delay on this flight costs
13.7% of arrivals land a full hour or more behind schedule, against 8.3% nationally. Ninety minutes is the honest minimum for a connection 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 seven other city pairs in the data, including SFO to SAN (156), SFO to SEA (111) 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. 357 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. 13.7% 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.
Related
Where to go next
- ORD to SFO, every carrier and departure
- SFO to ORD, the return direction
- United Airlines 2179 on the same route45.9%
- American Airlines 1253 on the same route66.3%
- Chicago O'Hare International (ORD) delay statistics
- San Francisco International (SFO) delay statistics
- United Airlines on-time record
- Every United Airlines flight number with a record
- The most and least reliable flight numbers in the US
- Why the first flight of the morning is statistically safest
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, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.