Frost is ice that clings to things such as leaves, branches, or, in this case, a window pane. If you sit next to the window in an airplane, you can see some frost on the window. It is cold outside the plane and the air trapped in the window cannot hold as much water anymore, so it condenses onto the window and freezes.
＜霜＞
霜は、葉っぱや枝に付いた氷です。この写真では、窓ガラスに付いています。飛行機で窓側の席に座れば、窓に付いた霜が見えます。外気が冷たいので、窓に付いた空気が凝結して、氷になり霜になるのです。
