If it's just in the 40's maybe, down to 32, and I'm only out for 3 days. I only carry what I'm wearing, maybe an extra pr socks, underware. Got a Marmot Precip (12 oz), don't take (rain) pants. Fleece jacket (R2)...10oz. Fleece pants for camp...12oz. Take a Patagonia Capilene LW crew (long sleave)...6oz. 2 pr. LW shorts w/liners...8oz. Hat, gloves, liners, ear fleece...10oz. That's about it with the carry bag....weigh less than 5lbs!