From what I've read cupboard should be fine. I use the fridge personally, as there seems to be a melting point for ghee that is at the higher end of room temperature. When I go to the indian grocery, in the winter the ghee on the shelves is solid. In summer, its part liquid.
Rather safe than sorry I just use the fridge and spoon out what I need.
I don't buy the plastic jarred ghee anymore. For some reason homemade has a far superior taste and aroma. I use ghee whenever I have it in my pilau, butter chicken and korma.
-- Josh