Good question: as I was just out hiking in the August weather...

My pack with water is 8.6 pounds.

that includes:

Camblback HAWG with 2 liters of water
first aid/ survival kit ( detailed elsewhere)
cell phone
small binoculars
rain Jacket
tiny susnscreen

Carried/ worn:

Hat, sunglasses, keys, knife, map.

adjustments for future hikes -- replace granola bars, get compass (!) bug dope, get map with UTM markings.

Teacher