I know if my house is locked up during the daytime and then I come home it is unbearable until all the windows are opened up, does everyone have air conditioning then?
In the US almost everyone has air conditioning. I remember last summer when there was a massive heat wave in europe I couldn't understand why it was such a big deal, it took weeks before it finally dawned on me that other countries aren't like the US and air conditioning isn't the norm.

Both of my cats are indoor only, just too many risks. Maybe if I lived in a different area I could take them out on a leash or sit in the yard with them so they could play. Where I live the best sitatation is for them to be inside only.