CrazedHoosier said:Do these cacti... go dormant in the winter? 
Dunno for sure, but mine tend to come inside during the cold spells and I try to avoid giving them water during the winter months. My winter months are likely shorter than yours and interspersed with some nice weather. NONE of my cacti and succulents like to be wet during cool temperatures, but certainly there are a couple of succulents that tend to grow during the winter months. Those I try to situate near light and when/if I can determine the cold tolerance they are outdoors. Water is still very minimal during that time. I fine most of them can tolerate temps to near 32F with some exceptions which clearly prefer warmer temps. I can't really find a guide for cold tolerance on many, so it's an experimental learning process that sometimes has a downside.
