If you’re handling extremely cold temperatures, have poor circulation, or tend to be cold-sensitive, grab at least a midweight set like the Smartwool Women’s Classic Thermal Merino Base Layer Crew or bump up to a high percentage of wool like the 100% wool Kari Traa Rose Half Zip Baselayer Top and Rose High Waisted Baselayer Pants.
For all-around recreation and use in average winter temperatures, the midweight First Lite Kiln Long Jane and First Lite Kiln Hoody are also great options.
Cardio intense activities, like running or cross-country skiing or backcountry tours, and warmer winter days are a good time to opt for lightweight base layers like the Helly Hansen Women’s HH LIFA Long-sleeve Crew Base Layer or the Ortovox 185 Rock’N’Wool Short Pants and Ortovox 185 Rock’N’Wool Long Sleeve.