Numbers from Aug 2025 – Jul 2026 flight records · generated 1 October 2026
GateCast grades your connection from A to F on how likely you are to make it, using a year of real flight records. At San Francisco, pairs of United flights scheduled 45–59 minutes apart were missed on 20% of the days they ran, Aug 2025 – Jul 2026; pairs 90–120 minutes apart, on 7%.
How often United connections here were missed
Every pair of United flights at San Francisco (regional flights sold as United included), grouped by the scheduled time between them, and checked against what actually happened on each day both flights ran, Aug 2025 – Jul 2026.
"Missed" means the first flight was cancelled, or arrived too late to leave about 31 minutes to get off, reach the next gate and board before the doors close. That time is our estimate for United connections here: flight records don't say which passengers made their connection. Days when the second flight was cancelled aren't counted. Pairs scheduled less than 35 minutes apart are left out, because we can't tell which of those the airline would sell as a connection.
When United connections at San Francisco go wrong
From the same flight records as the chart above, and with the same meaning of "missed".
How long a connection to look for
United connections of 90–120 minutes here were missed on 7% of days. No shorter connection time in the chart above was missed on fewer than 1 day in 10.
Time of day
United connections of 45–59 minutes at San Francisco were missed on 11% of days when the first flight was due in before 10:00, and on 28% when it was due in at 18:00 or later.
| First flight due in | 35–44 min | 45–59 min | 60–89 min | 90–120 min |
|---|---|---|---|---|
| before 10:00 | 24% | 11% | 6% | 3% |
| 10:00–13:59 | 34% | 24% | 12% | 6% |
| 14:00–17:59 | 32% | 19% | 11% | 7% |
| 18:00 or later | 37% | 28% | 18% | 11% |
Share of days missed, by scheduled arrival time (San Francisco local time) and scheduled time between the flights. "—": fewer than 500 days to go on.
Time of year
The month with the most missed United connections at San Francisco was June 2026: 18% of days. The fewest was March 2026: 8%. The first flight was cancelled or diverted most often in January 2026, on 1.7% of days, against 0.2% in September 2025.
| Month | Days missed | First flight cancelled |
|---|---|---|
| Aug 2025 | 8% | 0.7% |
| Sep 2025 | 8% | 0.2% |
| Oct 2025 | 9% | 0.3% |
| Nov 2025 | 13% | 1.7% |
| Dec 2025 | 12% | 0.7% |
| Jan 2026 | 11% | 1.7% |
| Feb 2026 | 12% | 1.1% |
| Mar 2026 | 8% | 0.7% |
| Apr 2026 | 15% | 0.6% |
| May 2026 | 18% | 0.6% |
| Jun 2026 | 18% | 0.6% |
| Jul 2026 | 17% | 0.9% |
"First flight cancelled" includes flights diverted to another airport. "—": fewer than 500 days to go on.
The last flight of the day
Of United's scheduled flights leaving San Francisco at 18:00 or later, 45 of 132 are its last flight of the day to that city: miss the connection and the next United flight there leaves the next day. Before 10:00 it is 1 of 113. Connections onto a last flight of the day were missed on 17% of days; connections with a later United flight to the same city, on 12%.
How late United flights into San Francisco ran
Over 57,445 scheduled United flights into San Francisco, Aug 2025 – Jul 2026, 28% arrived 15 or more minutes late and 10% an hour or more late. The typical flight arrived at the gate 3 minutes early. 0.9% were cancelled or diverted.
What decides a connection at San Francisco
- At San Francisco, half of travellers arriving from abroad without Global Entry waited 18 minutes or less at passport control, and 1 in 10 waited more than 43 minutes (24 September 2025 – 23 September 2026).US Customs and Border Protection, Airport Wait Times (awt.cbp.gov), 24 September 2025 – 23 September 2026, checked 25 September 2026
- Almost all international arrivals at San Francisco collect their checked bags, clear US customs, check them in again and go back through security before the next flight. On some routes, eligible connecting passengers skip the bag recheck but still go back through security: for example, United from Sydney (since September 2025, according to United's announcement, which calls it a test). Check with your airline. Flights that clear US preclearance before they leave are also an exception. It runs at 16 airports (ten in Canada, including Toronto, Montreal and Vancouver, plus Dublin, Shannon, Nassau, Bermuda, Aruba and Abu Dhabi), though not on every flight from them; a flight that clears it arrives at San Francisco as a domestic flight. Your airline can tell you whether yours does.United Airlines release, "United launches CBP's International Remote Baggage Screening on select international flights", 29 September 2025 (PR Newswire); US Customs and Border Protection, help.cbp.gov article 1244; US Customs and Border Protection, Preclearance locations and hours (cbp.gov/travel/preclearance, last modified 24 June 2026); Aer Lingus, "US immigration and pre-clearance" (mediacentre.aerlingus.com: no preclearance on its late Dublin departures to New York and Boston), checked 1 October 2026
What real connections here look like
Real United connections at San Francisco from last year's flights. Each is the typical case of its kind, not the worst we found. Schedules change, so these exact flights may not run on your date.
45 minutes between flights looks tight — but on 86% of the 71 days both flights ran, the first one got in with enough time for a typical connection here. Graded B.
Graded over the 71 days both flights ran, Aug 2025 – Jul 2026 · generated 1 October 2026 · local times
1h 30m looks like plenty of time. But the first flight arrived more than an hour late on 27% of the 72 days both flights ran, and the connection was missed on 22% of them. Graded C.
Graded over the 72 days both flights ran, Aug 2025 – Jul 2026 · generated 1 October 2026 · local times
3h 47m between flights looks like plenty of room. But this is the last United flight of the day from SFO to RNO: miss it, and there's no later one that day, however long the wait was. The first flight got in too late on 4 of the 153 days both flights ran. Graded D; with another United flight an hour later it would be B.
Graded over the 153 days both flights ran, Aug 2025 – Jul 2026 · generated 1 October 2026 · local times
These are two separate tickets, not one booking. If the first flight runs late and you miss the second, you're not owed a seat on it. Passengers typically paid $135* one way from SFO to LAX. Graded A.
Graded over the 71 days both flights ran, Aug 2025 – Jul 2026 · generated 1 October 2026 · local times
Typical fare passengers paid, one way, per ticket, from the US DOT fare survey (Jul 2024–Jun 2025). Fare only; bags and seats extra. Today's price may be different.
Check your own flights
Connecting through San Francisco on different flights? Enter both flight numbers and the date.
Questions
Is 45 minutes enough for United at San Francisco?
Over Aug 2025 – Jul 2026, pairs of United flights at San Francisco scheduled 45–59 minutes apart were missed on 20% of the days they ran (1,859 flight pairs). Your own two flights can be much better or worse than that, so check them rather than going on the minutes alone.
Is an hour enough for United at San Francisco?
Over Aug 2025 – Jul 2026, pairs of United flights at San Francisco scheduled 60–89 minutes apart were missed on 12% of the days they ran (4,478 flight pairs). Your own two flights can be much better or worse than that, so check them rather than going on the minutes alone.
Read the full San Francisco connection guide →
- US Customs and Border Protection, Airport Wait Times (awt.cbp.gov), 24 September 2025 – 23 September 2026, checked 25 September 2026
- United Airlines release, "United launches CBP's International Remote Baggage Screening on select international flights", 29 September 2025 (PR Newswire); US Customs and Border Protection, help.cbp.gov article 1244; US Customs and Border Protection, Preclearance locations and hours (cbp.gov/travel/preclearance, last modified 24 June 2026); Aer Lingus, "US immigration and pre-clearance" (mediacentre.aerlingus.com: no preclearance on its late Dublin departures to New York and Boston), checked 1 October 2026
- Flight times, delays and cancellations: US Department of Transportation, Bureau of Transportation Statistics, On-Time Performance, Aug 2025 – Jul 2026
- Fares: US DOT fare survey (DB1B), Jul 2024-Jun 2025
Grades are estimates, not guarantees. Always check your airline's minimum connection time.
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