When were cars first offered with air conditioning as an option?

Answer 1

I heard of one ammonia (very dangerous if it leaks) system in a car in the 30's. That was likely a one-off design.

The development of freons (starting in 1928) made small household refridgerators practical in by the 1930's and by the early 1950's, factory installed automotive A/C was offered.

Answer 2

I'm not certain, except that I recall that my Dad's 1967 Cadillac had air.\, while my aunt's 1966 Pontiac did not.