Back in the 60's I remember a summer where 86F (30C) was recorded and this was seen as nearly incredible. Now we have had 43C and that casued me to spend out on an aircon for the house. A car without air con is probably worth a lot less these days and in last years teperatures almost unusable as well as verging on unsafe.
In the mid 90's I remember turning down a car with A/c as it was £180 more than the one I bought. I had a sunroof and it was a white car so stayed cooler anyway. Now I think a/c is highly desirable if not essential.
The difference in price with and without air con on an older car is not much, but saleability of the one without is now not great, so no, I wouldnt buy one without unless it was VERY cheap,