This fort is a little wild, but I am getting a big difference in FPS from having temperature on to off.

Off FPS fluctuates between 60-80 FPS, on FPS is between 35-45.

Also, be careful! Sometimes the game crashes when moving over layer -7 (And sometimes other layers, but -7 stands out for whatever reason). Its not consistent, but it happens once a season, so autosave on if you care.