Let There Be Snow!

So apparently the newest "thing" at school is that if you wear your PJs inside out and throw ice cubes at the window, it will snow. Assuming you don't break the window and get in lots of troubles with your parents that is... but I digress. Of course it doesn't really say how soon it would snow... Technicalities.

Jared: I'm going to wear my PJs inside out and throw ice cubes at the window.

Me: Well, we don't have any ice cubes.

Jared: but... okay, then can I throw cold water at the window?

I guess it's cold enough out that the water might just hit the window and become ice.