Wooden shed with the door open so a few degrees warmer than outside so at present around 0 if I leave a drink on the bike it’s turned into a slushie for next session. Sometimes I end up with a fan heater blowing at feet during the warm up before putting the big cooling fan on. Favourite part of training this time of year is walking back to the house in just shorts with steam pouring off me.
I do wonder about the health risks of being so hot and wearing very little in a fan despite the fact the ambient temperature is slow low.