It came to me in a flash today while walking - a fool-proof method to determine easily if a place has a "perfect" climate - simply go to visit a few of the fancy hotels. If the main lobby/entrance areas are built without walls, windows, or screens but rather, are open to the elements 24/7/365, that is an important point to note. It means the temperature spread always is comfortable and the bugs are never too bad. Any big hotel corporation likely didn't spend millions building a hotel that is wrong for the climate. If you find that, you can start looking for a place to live.
Palm trees and ocean proximity are also nice features in a perfect climate.
Having enough shade is important, too, since a perfect climate will be warm. A shade "tree" like this is a unique approach These homeowners are from New Hampshire. It was startling to see their vehicle with New Hampshire license plates down here. It's the first one we've seen since arriving in Mexico seven weeks ago. (And no, they didn't drive all the way - they drove to Ft. Lauderdale, Florida, put it on a ship to Puerto Morelos, Mexico, and then drove the last hour home.