It’s Frigid February here at Undies101 and we’re talking about what we do to stay warm in the colder months. It’s been absolutely frozen in NYC the last few weeks…not as cold as Boston, but still. 
Anyway…I try and layer up when I have to stay warm…learned from years of skiing and then working hours and hours and hours outside in the cold on set. Start with whatever underwear you’re wearing for the day and then add the other layer on top…like these blue long johns. 
They keep things light underneath jeans, but keep the warmth in well. That’s how I layer up and stay warm in Frigid February! 