I made muffulo wool parkas for my colonists for the winter and they worked extremely well. However, when summer came around the colonists would not take them off unless i told them to and by that time i had forgotten they had them so i just had colonists burning up because they refused to take them off themselves. They were not forced to wear it either.
I sent a colonist in a caravan to another town and they died of heatstroke on the way because they had a parka on and they wouldn't take it off and there was no way for me to make them take it off.
You can take it off by forcing or in the caravan gear tab, by dragging it off them.