The legal drinking age in California is 21. Expect to have your ID checked if you look under 30, especially in bars and clubs, but also in restaurants and wineries.
Cigarette smoking has been all but criminalized throughout the state of California. Don’t expect to find a smoking section in any restaurant or an ashtray in the bars. Smoking is illegal in all bars and clubs, but your new favorite watering hole might have an outdoor patio where smokers can huddle. Taking the ban one step further, many hotels, motels, and inns throughout the state are strictly non-smoking, and you’ll be subject to fees of several hundred dollars if your room smells of smoke when you leave.
There’s no smoking in any public building, and even some of the state parks don’t allow cigarettes. There’s often good reason for this; fire danger in California is extreme in the summertime, and one carelessly thrown lit butt can cause a genuine catastrophe.