As someone from the equator with hot and humid air, this thing is common, it allow hot air in the attic to escape so the hot attic won't radiate into your house, while sucking fresh air into your house. Plant surrounding your home exterior also will help with the cooling as well, especially when it stop light from hitting your wall. I usually just open everything during day, but open everything during night will also help circulate the hot air heated by the heat-trapping concrete wall. As of now i can't open during night because my cat will escape, so i just use ac for half hour or so.
Yeah the mozzy mesh is a life saver, for both mosquitoes and flying termite/ant swarm after rain, but do keep in mind that meshes will restrict some air flow. Still, it's better than nothing, and combine with that rooftop onion you might get better result.