Training in the dark

I really struggle with training during dark evenings. By rights, when it gets dark, that's me preparing to snuggle down, and to try and break that is incredibly hard. I wonder what is the right combination of clothing to wear depending on what the temperature is. What if I get too hot, too cold. What would I do with excess clothing I don't need to wear. (Even now my children are snuggled in their duvets watching TV.)