I have not gone more than a few days, when it,s cold. What works best for me, is to fast in summer, preferably when it's almost too hot.i then am completely comfortable, while others are wilting. I find it hard to be cold, particularly to have cold hands. Drinking boiled water might help a bit... even in the heat of summer, I wanted hot water... and to be able to break the fast and reseed on ripe fruit and veg.