When you suddenly have to take a piss because of a large fluctuation in temperature. Like form an eighty degree day to the nice, cool, sixty five of your house.
When you get up in the morning, you take a piss. Seconds later, you're in the (hot, steamy) shower, and you have to take another piss. But, instead of getting out, you just end up pissing all over the tiles of the shower. Here is a clearly defined Climate Piss.