While it's never too cold, wet, hot, dark, etc. for me to ride, I can ride any of my bikes in my house. I own it and can do whatever, whenever. My most often indor endeavors are trials style on fat tires though.
Me and the kiddo do circles in the basement even if its a nice day out! This is the bike i cruise with her. She is on a balance bike making the transition to her first belt powered 16" peddle bike. Shes all ready hitting the half pipe at the skate park!