Not sure if it makes a difference. I keep all my Festool tools in the house, except the Kapex which is too heavy and too big to move. My shop can be very cold, well below freezing point and I don't know about its effect on grease.
I have seen some people reporting grease leak in this forum, but in all my life of woodworking, I have never experienced one single tool grease leak on any of the brands of tools I have owned, whether they are portable or stationary. I use some tools regularly and some just once in a few months or much longer (e.g. the nailer or some of the routers). I am sure my tablesaw will never leak, if grease leak is due to inactivity.