How can I shower without hot water?

there isn't any hot water i have no idea why, but I really need to take a shower today (its been a couple days since I showered my hair!). I managed to shower my body in the cold water but I can't take doing my hair in it. it is bitterly cold outside right now 0 degrees so I don't want to get sick. Please do you have any suggestion on how to either cope with it or make it hotter?? thanks!