1. Countries in colder climate are generally more economically prosperous. South Korea is colder (though hot in summer) than S/E Asian countries.
2. South Koreans have always been overzealous about education.
3. South Korea is ethnically more homogenous than S/E Asian countries. People have been comfortable with idea of putting interests of the large group (i.e. nation) before that of the individuals.
Singapore and Taiwan are very much so. And Singapore is right on the equator.
https://web.stanford.edu/~mburke/climate/BurkeHsiangMiguel_F...
https://www.dailymail.co.uk/news/article-8477297/Why-colder-...
the war was supposed to sink them according to european leaders and yet they are stronger than ever.
Perhaps it's more accurate to say that this factor is conducive to forming empires, not just cultures. Of the four classical cradles of civilization (China, Egypt, India, Mesopotamia), only half fit this winter criterion, so it's clearly not a prohibitive factor for the formation of a civilization; perhaps just for its technological development and dominion over others.