Key takeaways
- Midday Asia departures (like SFO–TPE UA 871 and SFO–NRT UA 837) clear upgrades more often than the late-night “Asia bank.”
- Europe routes like SFO–LHR and SFO–FRA are the hardest. Sunday and Monday evening departures are almost impossible to clear.
- Premium Plus > Economy. Booking Premium Plus gives you better upgrade priority, and it often clears when Economy requests don’t.
- Aircraft size matters. The 777-300ER has 60 Polaris seats vs. 48 on a 787-9. More seats means better upgrade math.
San Francisco is one of United’s strongest Polaris hubs, with multiple daily flights to Asia and Europe. But if you’re trying to use PlusPoints or miles for an upgrade, not all flights are created equal. Some clear days in advance, others leave people stranded at #1 on the waitlist until boarding. If you’ve ever wondered whether it’s smarter to book the midday Taipei flight or the late-night London run, here’s what flyers actually see at SFO—and how you can tilt the odds in your favor.
Want live upgrade clears for tonight’s SFO departures? Flyers post them daily in the TalkTravel Polaris forum.
Why SFO upgrade odds are unique
SFO sits at the intersection of tech and Asia. That means corporate contracts and premium-heavy demand dominate certain flights, especially the evening Asia bank and the nightly London departures. A United gate agent recently confirmed to flyers that SFO–LHR on Sunday evenings is one of the toughest upgrades in the network because corporate travel locks most seats.
Midday Asia departures tell a different story. On routes like SFO–TPE and SFO–NRT, frequent flyers report upgrade clear rates above 80–90% on weekdays, compared to less than 30% on peak evening flights. It’s the same aircraft, but the passenger mix changes everything.
Upgrade odds by route and timing
| Route | Best Timing | Worst Timing | Notes |
| SFO–TPE | Midday (UA 871 ~12 p.m.) | Evening (UA 853 ~10 p.m.) | Midday clears up to 90%, evening often sold out. |
| SFO–NRT | Midday (~11:30 a.m.) | Evening | Business traffic loads evening flights heavily. |
| SFO–SIN | None (only evening nonstop) | Always tough | Flagship Asia route with high paid demand. |
| SFO–LHR | Tue/Wed departures | Sun/Mon evenings | Consistently oversold on Sun nights. |
| SFO–FRA/CDG | Midweek | Fri/Sun | Conference-heavy routes, hard clears. |
Note: Aircraft swaps also impact odds. The 777-300ER has 60 Polaris seats; the 787-9 only has 48.
PlusPoints and fare class
Polaris upgrades at SFO are governed by the standard United priority order:
- Global Services (always clear first).
- PlusPoints and miles (instrument-supported upgrades).
- Status and fare class (1K > Platinum > Gold, and Y/B/M fares beat K/G).
Booking Premium Plus instead of Economy makes a big difference. It costs 30 PlusPoints to jump from Premium Plus to Polaris versus 40–80 from Economy. More importantly, Premium Plus clears first. One 1K reported booking Premium Plus to Tokyo midweek and clearing every time, while his Economy waitlists often failed.
Flyer-reported patterns
- Asia midday flights clear more than evenings. One flyer on Flyertalk reported a 90% success rate on SFO–TPE midday flights vs. almost zero at night.
- Europe is brutal. Even high-status travelers have been stuck at #1 on the SFO–LHR Sunday night list without clearing.
- Aircraft swaps help. Flyers track UA 837 (SFO–NRT) and note higher clear rates when it’s a 777-300ER with 60 seats instead of a 787-9 with 48.
- Check seat maps. Tools like ExpertFlyer and UA’s own app show if “PZ” upgrade inventory exists. If not, your odds are slim until day-of.
FAQs
Do midday Asia flights really clear more often?
Yes. Frequent flyers consistently report that UA 871 to Taipei and UA 837 to Tokyo midday flights clear at far higher rates than the evening Asia bank. It’s the same planes, but the late-night departures carry heavier corporate traffic, making them harder to crack.
Which SFO routes are toughest for Polaris upgrades?
London, Frankfurt, and Singapore are the hardest. These routes carry a high proportion of paid business travelers, and upgrades rarely clear. Even Premier 1Ks often sit at #1 on the list without success, especially on Sunday and Monday departures.
Does Premium Plus give me a real advantage?
Yes. Premium Plus passengers sit above Economy in the upgrade order, and the PlusPoints cost is lower. Flyers often hedge by booking Premium Plus, which guarantees a more comfortable fallback seat if Polaris doesn’t clear.
When do most SFO upgrades clear?
Most Polaris upgrades at SFO clear within 24–48 hours of departure, but timing depends on the route. Midweek Asia flights often clear earlier, while Europe and Sunday evening departures go right down to the wire at the gate.
Does aircraft type affect my upgrade odds?
Absolutely. A 777-300ER with 60 Polaris seats gives you more chances than a 787-9 with 48. Savvy flyers even choose flights based on aircraft rotation, since more seats equals more potential clears.
Bottom line
If you’re flying out of San Francisco and chasing a Polaris upgrade, timing is everything. Book the midday Asia departures for the best odds, avoid Sunday night Europe flights if upgrades are your goal, and always consider Premium Plus as a strategic starting point. Aircraft swaps and route demand matter just as much as status and fare class.
Want to know which SFO–Asia flights are clearing this week? Join the TalkTravel Polaris Upgrade thread, where flyers share live waitlist positions, seat maps, and real upgrade results every day.
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