I was on UA 955 Dec 10 LHR to SFO (a 777-200), scheduled to arrive 12:55,
diverted to SMF. From what I recall of my Channel 9 addiction:

Coming into the Golden Gate 4 arrival, we were told to expect holding. Around 12:30 we hit Point Reyes (PYE) and put into holding. I believe we were second on this arrival, behind a Skywest (6437 - they would up going to FAT). Visibility at SFO was 400-600-1000 (as I understand it, that's at beginning, middle, end of runway). Norcal queried for our RVR (runway visual range requirement) and the response was 1200. About an eighth of the way (and around 25 minutes) into our third holding lap, our captain requested a divert. We were cleared direct SFO, SJC to land at SJC. Several minutes as we approached SFO (at 13000 not landing), the captain announced on the PA our divert to SJC. I was surprised at the amount of fussing on the plane, and ch 9. went silent (has no one been diverted?). During this time, our divert changed to SMF, explained later on the PA as there being too much traffic coming to SJC.

I'm curious about the 1200 response to the RVR inquiry. Isn't that a Cat II ILS length? Assuming so, do the United 777s and crews normally maintain a Cat III qualification, and this was an exception?

I'm surprised that we didn't stay in holding longer. 25 minutes doesn't seem that long, especially with us being about 10 minutes early at the point we entered holding. I never heard minimum fuel mentioned, although channel 9 had several blackouts. My guess now is that it wasn't so much a that our fuel was immediately getting low, as it was that with questionable airport availability it wasn't worth waiting being behind several other planes (SFO-wide). What are the requirements for doing a fuel diversion?

All in all we wound up getting to SFO about 3 hours late with "to the second" simultaneous landing with a CRJ (SkyWest 6437 - what a coincidence). Much better than I expected. I thought that with the number of planes diverted, along with those in the air taking precendence over us waiting at SMF, we'd be far worse. BTW, us being international didn't give us precendence over UA135 from ORD-SFO (747-400) sitting next to us on the tarmac at SMF. The controller said he was requested to put whoever was faster at 11000, but figured that we'd both be the same.