Long hair is a hairstyle where the head hair is allowed to grow 
Who are those with long hair?
what constitutes long hair can change from culture to culture, or even within cultures.
So what culture are we talking about?
for instance,a woman with chin-length hair in some cultures may be said to have short hair, while a man with the same length of hair in some of the same cultures would be said to have long hair.
I know Indians use to have long hair
alo,Males having short, cut hair are in many cultures viewed as being under society's control, such as while in the military or prison
Does having long hair  have to do with weather?