I've never been cold on some really cold, windy nights and as long as you have a good pad beneath you it is hard to go wrong. I'm not a big guy 5'-9"/160lbs but I still got the long version so that I can stuff any extra clothes, water bottle, etc. in the bottom of the bag at night. I've been using a Thermarest Z-Rest foamy and an inflatable Prolite but I think that I'll finally grab an Exped Downmat. They weigh a bit more but I've had way too many people raving about them and getting more sleep than me.