The second one is the correct option, because you’re asking a question, and the structure of the question usually requires the “will” to be the first, and then the subject. :) I hope it helps!

Hello, Eli. You could say, "How will the weather be tomorrow?" Although it sounds more natural to ask "What is the weather going to be like tomorrow?" I hope this answer helps. If you are interested in taking English lessons, I am a professional teacher on Italki. I am currently accepting new students and would be happy to work with you.

Hello, Eli! La segunda es mejor porque se requiere el verbo después del sustantivo cuando hay dos partes del verbo (como will y be). Si haya solo una parte (el presente, no el futuro), entonces la frase será --> "How is the weather right now?"

What will the weather be like tomorrow? This is the most common in my experience as an American.