Very warm as part of the ECWS system base layer. Headed out on a cold weather snowshoe climb next week planning on using these at the summit. Hoping to receive the fleece lined FR balaclava in time to use as well. I have been very pleased with the gear I’ve purchased from Camolots, especially the FR base layers after having caught fire last year and burned with UnderArmor base layers that stuck to my skin. Savings is tremendous compared to purchasing new commercial FR.