I'm mostly a lightweight dry sack guy for all my individual shiz like sleeping kit and food. But...went on a recent epic NW Alaska char adventure and was tapped out at 75-lbs of gear with food, clothing, survival equip and packraft, plus camera gear. I'm using a bad ass Kifaru Timberline pack that weighs somewhere around 8-lbs dry and empty. So, the scenario we faced on a 20-mile hike start day was a full day of rain. I didn't bring a pack cover, only dry sacks inside to keep my stuff dry. I weighed the pack soaking wet and it was about 17-lbs empty.
So, an added 9-lbs of water weight (1.3 gallons of water) and you'd feel that weight on the walk. Just something to consider if you're hoofin miles. Maybe a pack cover would save you nearly 10-lbs of water weight in a heavy rain spell.
My lightweight dry sacks are made by Seal-Line. Rock solid waterproof. worth the cost up front, IMO.
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