You’d better put on your jacket, for it’s windy outside. 和 You’d better put on your jacket because it’s windy outside. 的差別在哪裡？如果不好說明，請提供一些例句。

The meaning is the same, but the second sentence is much more natural. Using "for" to mean "because" is mostly archaic: it occurs often in Shakespeare, but not in modern everyday English. If you said the first sentence in conversation people might understand you, but it would sound very strange.

Actually, I think most native speakers would say this: "You'd better put on your jacket; it's windy outside." The word "because" is implied here and doesn't have to be spoken.