https://en.wikipedia.org/wiki/Great_conjunction gives the exact time as 21 December 2020, 13:22:00 UTC, or 5:22 AM PST. In SF, the planets will set around 7:10 PM, the sun sets about 5pm. So if my best observation time will be around 5:30 or 6pm, seems like they will be at least as close if not better on the 20th as the 21st, right? And then even more so for HI, two hours later.