Classic Thermal Merino Base Layer Bottom

Smartwool's Classic Thermal earned its place because 250 g/m2 interlock merino does two things synthetics cannot: it keeps insulating when damp, and it stays wearable for most of a week without smelling. If you sleep cold at altitude or break camp from frozen tents, this is the bottom you want. The problem is that midweight is a narrow window. At 250 g/m2 it is too warm to hike in much above 40 degrees, so you sweat through on the first climb and then carry a wet layer all day. Treat it as a sleep-and-camp piece plus genuine winter travel, not a three-season bottom. The other honest issue is durability against price: premium money for a knit that thins at the seat and knees under a hipbelt, with pinholes showing up within a season or two of steady use. Merino-nylon blends last noticeably longer, and 200 grams is not light.