I use the same base layer top from about 10 degrees to however hot it's going to get- the Sitka Core Lwt Hoody, bottoms if it's warm Smartwool merino boxers, if cool (but above ~ 10 degrees) some very lightweight merino bottoms from Montbell.
If it's cold though (usually single digits or lower) I use a Patagonia's Capilene Thermal Weight hoody and bottoms. I originally bought the top to use a mid-layer, I didn't think it did great in that role, but found it worked really well as a cold layer base top. Shortly after bought the bottoms. Mine are ten years old and the names have undergone at least three changes, but currently Thermal Weight.
They use a pretty light Polartec Micro Grid fabric- pretty light the hoody is 7oz, the bottoms 4.7 oz, but pretty darn warm for the weight
Looks the hoody might be discontinued, they make a zip top
https://www.patagonia.com/product/m...3657.html?cgid=mens-baselayers-thermal-weight
https://www.patagonia.com/product/m...ayer-bottoms/43687.html?dwvar_43687_color=BLK
What's everyone else use when the mercury really drops?
If it's cold though (usually single digits or lower) I use a Patagonia's Capilene Thermal Weight hoody and bottoms. I originally bought the top to use a mid-layer, I didn't think it did great in that role, but found it worked really well as a cold layer base top. Shortly after bought the bottoms. Mine are ten years old and the names have undergone at least three changes, but currently Thermal Weight.
They use a pretty light Polartec Micro Grid fabric- pretty light the hoody is 7oz, the bottoms 4.7 oz, but pretty darn warm for the weight
Looks the hoody might be discontinued, they make a zip top
https://www.patagonia.com/product/m...3657.html?cgid=mens-baselayers-thermal-weight
https://www.patagonia.com/product/m...ayer-bottoms/43687.html?dwvar_43687_color=BLK
What's everyone else use when the mercury really drops?