Semitropical means the same as subtropical: a climate that sits between the hot tropics and the cooler temperate lands. Summers are often hot and sticky; winters are mild, and hard frost is less common than further north. Taiwan itself is often called subtropical, so this is a map word about your home weather, not a rare jungle word. Gardeners and weather writers in the US still use semitropical now and then, but subtropical is the twin students will meet far more. Though actually, in everyday talk “tropical” just means “very hot, like a holiday,” which is looser than the map. Semitropical is trying to be more careful: warm, yes, but not fully in the tropical belt. Plants sold as “semitropical” can often live outdoors in a mild winter, but one cold snap may still kill them.

亞熱帶的（英語更常說 subtropical；台灣本身就常被稱亞熱帶）