I really can't say enough about Merino wool! Unless it is warmer than 90 degrees I don't see why you couldn't wear this everyday of the year! I wear this thing all the time. On it's own it looks great and is really soft to the touch. The temperature regulation is awesome. My favorite use it underneath my softshell when I am on the crappy PA slopes, night skiing they are blowing snow and it's 20 degrees but I am still warm and the same range of motion as I have in my birthday suit!