20 degrees is warm enough for t-shirt and shorts. xD Once it's down to about 10-15 degrees, then I start wearing sweatshirts, cardigans or jerseys. Below 10 degrees I may wear a jacket. Below 3 degrees there damn well better be snow! >8I
Lol where I live, anything above 19c is classed as a heatwave, but the minimum amount of clothing I wear contains an average outfit (t-shirt, plain pants) with a fluffy hoody. However, I wouldn't go around with something big and fluffy, since my average body temp is about 2c higher than average.