How much condensation should I expect on the inside of a bivi bag? Last night I slept my first night out in a bivi bag (in the garden!) I'm in the UK. There was a heavy dew and overnight lows were 7°c/ 45°f. My face was completely out of the bag. I was cosy warm but not hot. Inside of bivi was moist to touch, enough to make outside of sleeping bag damp, but no drips (Bivi is a macpac cocoon).