One of Chloe's biggest trademarks is her blue hair. Her blue hair not only makes her stand out in a crowd and is easily identifiable, but also expresses her rebellious and punk-like persona. Chloe is after all, a rebel. With her father dying, Max leaving, and Rachel disappearing (eventually), it's no wonder why Chloe became so unruly and rebellious later on in her life, and started to hate the world for being so unfair to her. As a result of all that, her blue-dyed hair became part of her image -- it's who she is.
In Life is Strange: Before the Storm, clearly, Chloe's hair is brown, so it would be very interesting to witness her undergo this "official" transformation/makeover, and finally let us see her change into the Chloe we all know and love. Perhaps we will even get to see her get that tattoo that is on her right arm as well?