I would wear a skirt in only 50º,
but you may end up freezing.
Though for girls in school,
most likely the only time you will go outside is in the morning going to school;
getting to your car (etc.)
Same goes for gals working in an office all day.
just to be sure you should check the highs and lows for your area.
If it is below 30º or around there,
it may be smart NOT to wear a skirt.
If you are feeling really brave,
wear leggings (or to stay on the safe side,
a nice warm pair of tights).
Try to match the color of your tights of leggings with your shirt or sweater.
TIghts are cute in patterns,
but for leggings you should try to stay with solid colors.
Personally I would wear a denim skirt,
but if you want to wear a sirt of other materials,
Of course I am writing this advice to a girl wearing a mini skirt or maybe even a knee-length skirt,
but if you want to
wear an ankle length skirt,
DO THAT TOO!
If you are planning to wear a rather long skirt,
try to avoid wearing leggings (they will not show)
and if you wear tights,
try to stick to natural colors.
Once again personally I would wear a cloth skirt and not denim,
if it were to be long,
but on other days I might wear a long denim skirt with a patterned shirt and a matching denim jacket.
My ideal mini skirt outfit would be a denim miniskirt with one of my favorite t-shirts that is very decorative and reads "Life is good` This I would pair with my dressy black street shoes and funky patterned flower tights or a black pair of leggings.
That is my idea of a cute outfit with a mini skirt,
but I`m sure yours wil vary!
Have fun and the best of luck!