Cold water, most of the time followed by cold weather. Most of the time somewhat shitty shell bottom, the further south you go on the beach, the better it gets though. I would say high tide would be the best, due to the slope of the bank, but pretty much any time will do. Hardly any people AT ALL. You would be lucky during a weekend midday to find 15 people on an entire mile or two of this beach.
I would say look on mapquest.com for the best directions, but basically, take 101 North almost all the way through Eureka until you see the Samoa bridge exit to the left(you will turn on the street right in front of the Pizza Hut. Then drive over both bridges, and at the bottom of the second bridge, turn left. Then drive for approx. 1-3 miles until you see the pulp mill. Then just stop at any little side street, or turn out you feel like. The best spots to park are the turnarounds(many local parties are held at these beaches on any given weekend as well)GOOD LUCK!