Sir Sebastian said:
11-12 hours, assuming there are no delays, which there always are
Given that you're likely flying into SFO, chances are highly likely. I flew in yesterday from Chicago, and fortunately had no delays. However, note that the Left Coast is getting battered by some monster winter storms (for us, that is): winds off the coast are literally up to 140 km/h, waves are over 3m high, and some places in the North Bay are getting dumped on by over 20cm of rainfall within 24 hours last night.
Translation: SFO is likely going to have one of its runways closed down due to weather, as often happens, cutting the air traffic throughput in half. So when flying out of London, Sebi, pack a meal and prepare to circle the Peninsula a good 4-5 times. :frown: