Cannabis is set to be legal in California on January 1, 2018; however, this is the day in which California starts to issue out licenses & permits. You will legally have to be over the age of 21 in order to purchase.
No one truly knows at this point in time when the first day of actual retail sales will take place.
All Cities / Counties in the State of California can choose to allow recreational cannabis or to ban it as well.
The major difference between Medical Cannabis vs. Recreational is as follows:
Beginning January 1, 2018, two new cannabis taxes apply as follow:
A 15 percent excise tax is imposed upon purchasers of cannabis and cannabis products. Retailers of cannabis and cannabis products are required to collect the 15 percent excise tax from the purchaser based on the average market price of any retail sale and pay it to their cannabis distributor.