英訳はこの下ですよ〜！　↓

A: They say we should wrap up warm if we go to the mountainous areas.
B: But it's summer! It's so hot!
A: I know, but in the mountains, apparently the temperature goes down really low. We should listen to someone who knows better than us.
B: Right, OK.

●注釈●
wrap up warm 　暖かく着込む
mountainous 　山の多い
apparently 　聞くところによると
temperature 　気温