"How cold will it be tomorrow?"
With 多 and the measure-word included in the statement at the end, they form a question. Breaking the target translation down, we have:
明天 - Tomorrow 会有 - will be (lit. will have) 多冷 - how cold
So the question can be thought as "How cold will it be tomorrow?"
I looked it up, and duo means "many, much, numerous, odd, excessive," not how many. I think the literal translation is "tomorrow will have many cold." or "tomorrow will be very cold." I don't understand how this is a question.
You're right. I didn't look far enough. But how can you tell if its a question or a statement? Is is just context?
can someone explain why "明天会是多冷" is not acceptable? 会是 means "will be" and "会有" means "there will be" it seems 明天会是多冷 should be acceptable
是 + adj. makes no grammatical sense in Mandarin. A probably correct version could be 明天会是多冷的天? But dont quote me, I'm not native.