I live in southwest Florida, so no cold weather challenge. My needs are light block, bug deterrent, and not getting too hot.
When bugs are bad, I wear an ultralight sun jacket with a long hood. It adds almost no insulation and breaths well, but keeps the bugs off. The hood helps, however, it is not fully light blocking.
When I want to block all light, I use the detachable uninsulated hood that is usually stored in the neck pocket of my Eastern Mountain Sports ski coat. The hood has tabs with Velcro that extend around my neck, so it stays on without the coat. It extends out a good distance, completely blocks all light, and since it's uninsulated and allows heat to radiate out, I stay cool enough.
During summer sessions, I also wear ultralight uninsulated hiking pants. Like the sun jacket, I do not overheat int he pants, but they keep the bugs off.
Gary