I often see 100% nylon pants a lot in stores. What properties does it have that make it effective when hiking? Is it effective in all seasons or just under certain conditions?
Nylon dries fast, is resistant to ripping and tearing, and fairly breathable. This makes a nylon pant great for 3-season conditions. In colder season weather it can be easily layered with baselayer leggings to provide additional warmth and wick some sweat.
Alternatives to the typical nylon hiking pant/short are running shorts and softshell pants. Running shorts are even more breathable and dry even faster simply because there's less to them. Softshell pants are more expensive and will dry slower but provide additional protection against light precipitation and wind.
Nylon, among other synthetics, is an ideal material for clothing for most outdoor pursuits for several reasons. I will use the example of cotton as the traditional fabric for comparison:
This is not an exhaustive list of the attributes of nylon, but provides the main reason it is a "go to" fabric for outdoor gear.
Polyester has similar characteristics to nylon and is another mainstream synthetic fabric. Merino Wool is a natural, renewable material that offers many of these same benefits that nylon does, with the exception of the superior durability provided by nylon.