Actually, there are only two seasons, both can be hot. April though September is the rainy ( monsoon ) season, and quite humid as well. October through March is dry season ( much more tolerable ). But as I said, where I go there is generally a nice breeze. I plan on Wintering in the Nam, and Summering here..I had a colleague from Vietnam who used to say that there were only 3 seasons there.
Hot, very hot, and extremely hot.