The winter season is very stressful time for a newly planted plant. According to me, the best time to plant planting is during early summer because this time Californian soil temperatures are on the increase.
Honest answer : Unless you light dep your crop. June 5th is when outdoor growers in northern cali ( the 15-20 that I know ) throw their plants outside. I believe thats when the plant gets enough sun to not flower but grow. This is like Trinity county area.
It depends on where in Ca. you want to grow. The further north, the later to plant. Where I am located, May 15 is the earliest. Southerners plant earlier, northerners plant later. Some plant by the moon cycle.