One interesting thing about humans is that they never are completely fine with the temperature of a place. But is being too cold worse or being too hot worse? The argument that heat is worse is the side I will be choosing since I come from an equatorial country.
When It is hot, we usually switch on the air conditioning. The air conditioning does cool down a place but it can only do so to a specific amount. The temperature that the body wants to be in and the temperature we think it wants to be in are different. We can warm ourselves to the most comfortable temperature In a cold place with the right blanket.
cooler temperatures do increase susceptibility to diseases but keeping warm is not a challenge nowadays. The individual choices of people might vary but I would take a cold place over a warm one because of the reasons I have listed above.