Fall is cool and all, but the upcoming season can be frustrating. As the sun sets on summer, picking outfits becomes harder thanks to chilly mornings and hot-as-hell afternoons. Figuring out what to do with your hair is equally complex.Traditionally, going darker as the weather gets cooler seems like a no-brainer, but top colourists and their celebrity clients, like Bella Hadid and Kendall Jenner , are making a case for going brighter for autumn . That's where chestnut brown comes in.