I am relatively inexperienced, and planning a trip to Ecuador to climb Cotopaxi and Chimborazo. I've been buying extra-warm clothing for the trip. Yesterday in 20F/-6C weather, I went to my car wearing nothing but a T-shirt and dress pants after my workout (indoor). I was still sweating when I got home 30 minutes later.
I know everyone says to dress in layers, but a 60 degree ice slope might a bad place to remove my thermal long underwear. It won't get below maybe 10F here before my trip, I don't own an ice axe, and I don't have anywhere to use it if I did. How do I decide how much clothing to wear?