What you need to know about the launch.

What’s happening: As a result of California voters passing Proposition 64 in November 2016, the state will begin allowing commercial sales of cannabis to adults 21 or older on Monday, Jan. 1. Who’s selling: Marijuana will be available with proper identification to anyone 21 or older — state resident or visitor — at about 65 outlets scattered across the state that obtained local and state licenses, including Harborside, Purple Heart and Blum in Oakland; the Berkeley Patients Group and the Cannabis Buyers Club of Berkeley; 7 Stars Holistic Healing Center in Richmond; Sparc and Solful in Sebastopol; and Mercy Wellness in Cotati. Sales begin as early as 6 a.m. Recreational sales can’t begin in San Francisco until at least Jan. 6, and some conservative counties may not approve any sales for the foreseeable future. What already happened: Personal cannabis laws took effect earlier, in November 2016, allowing adults 21 or older to possess, transport and gift of up to 1 ounce of cannabis flowers to other adults 21 or older, as well as possess up to 8 grams of extract or infused foods, and grow up to six plants. Smoking in public is still prohibited, and marijuana remains illegal under federal law. Who’s paying: California will charge both recreational and medical buyers a 15 percent excise tax, which is expected to eventually bring in $1 billion or more a year for marijuana research, addiction prevention and boosted law enforcement, among other things. Recreational customers must pay sales tax as well, unlike those with a state-authorized medical identification card. In addition, cities can choose to impose local cannabis taxes. What about medical marijuana? For the state’s vast medical marijuana system, Jan. 1 is very much business as usual. Medical stores will remain open to patients who can show ID and a valid doctor’s recommendation to use cannabis. In the coming weeks and months, more medical dispensaries and delivery services will obtain state licenses to sell to recreational customers. For more information: Visit the California Cannabis Portal at www.cannabis.ca.gov or GreenState, The Chronicle’s digital magazine navigating the new cannabis culture, at www.greenstate.com.