This bag is super warm. We’ve tested it in 50 degree weather so far and I’m hot all night. I sleep with it open to cool off. That being said I think you’ll be warm in 35-40 degree.Great for backup this coming winterI’ve never been into extreme camping, but this bag has converted me. It keeps you nice and warm all night, make sure to cinch up the collar and hood. I got the 400g version, packs up nice and small, and super light. Well worth the money.I’m sending it back but wanted others to know you will be getting a sleeping bag that is filled with 30% of unknown and is over 50% heavier than listed.I was surprised the sleeping bag seemed heavier than listed. Upon checking the label I found that it actually is only filled 70% with duck down and 30% with ??? who knows what.I reread the description multiple times and nowhere does it state that it is only 70% down... except ON THE LABEL. Which of course you can't read until you receive the item! AND it even then it doesn't state what the OTHER 30% is!The Amazon description reads : "Premium Down Filled", "Down sleeping bag selected the best white duck down" "premium quality duck down", "down-filled", "This down sleeping bag", "premium quality duck down filling", "KingCamp down sleeping bag", and it also continues in the prodution description from the seller to refer to this as a white duck down sleeping bag... (even including a picture of white duck down!)Also it is NOT 2.2 lbs as listed, but 1.7KG – which is just over 3.74 lbs.This is a good item however my feet was cold it need abit more padding around the feet and lower legsGreat productGreat for grandchildren in our caravan ,got adult size so they can stretch and grow intoVery good productI'm 5ft 8 and this sleeping bag was too short for me, It is very thin and did not keep me warm at all. Used for camping in around 5oc temp.