What should I wear at the concert?

Me and my 2 friends are going to a hardstyle outdoor concert. It’s my first concert here in Denmark and right now the weather is sunny, after some minutes it changes to clouds and it’s just always changing. I m not sure what to wear and I don’t know if it’s cold or not.
I am thinking of wearing a black skinny jean, brown tee which says something in danish about “help others from poverty, and donate to contribute to their education” or something like that.
and then either boots. they are kind of like this.
then I don’t know with coat and stuff, it could rain idk.

I need your suggestions asap.

thank you in advance!