When cooling is (and isn’t) required
Generally, no. California landlords are usually not required to install or provide air conditioning, because state habitability law lists heat but not cooling. There are exceptions, mainly when the lease or a local ordinance requires it.
The state's basic standard for a livable home includes working heat, plumbing, safe electrical, and freedom from serious hazards — but not air conditioning. So a unit that never had AC is generally not a legal problem simply for lacking it.
That said, a landlord who provided AC with the unit, or promised it in the lease, usually has to keep it working. Some local governments are also beginning to address extreme indoor heat. So whether a landlord must provide cooling depends less on state habitability law and more on your specific lease and any local rules. If you are unsure whether your landlord owes you working AC, a free review can help.
This is general information about California tenant rights, not legal advice. Every situation is different.