Hi MLSly,
I’m not sure which mattress you are referring to here or whether you are comparing gel memory foam to regular memory foam, gel memory foam / latex combinations to memory foam or something else. Could you clarify what you wanted to compare?
That’s really a personal preference issue and only you can really decide on the relative importance of sleeping temperature (in any season) vs any of the other factors in a mattress purchase that may be most important to you. Most questions that have “should” in them are a matter of preference and involve weighing which of the tradeoffs involved are most important to you. I tend to think more in terms of the pros and cons of each choice rather than “better or worse” or “should or shouldn’t” terms. Certainly a mattress that sleeps warm for someone in normal climates would sleep warmer in a climate that is hotter or more humid but your own experience on other types of mattress in the past would also be a good indication as to how warm you tend to sleep.
Post #2 here also has more information about the many factors that contribute to the sleeping temperature of a mattress besides just the foam itself and all of these work together. Latex is generally a cooler foam category then either memory foam or polyfoam but all the other factors will also play a role regardless of what foam is in your mattress. All foam is primarily an insulating material (some less than others or course) so a mattress that is made of an innerspring and natural fibers will be more temperature regulating than most mattresses that contain foam (whether it’s memory foam, polyfoam, or latex foam) but these types of mattresses are usually more costly than mattresses that contain foam and for many people they are also not as comfortable.
Phoenix