Was the person making a statement or asking a question?
It is snowing = Statement of fact.
Is it snowing? = Question.
Colloquially, you will hear "It is snowing?" but it's not grammatically correct and learners are advised to avoid it. I don't mean only when talking about snow. I mean that what you should avoid is using the word order for a statement but then simply putting a question mark at the end to turn it into a question. That works in many languages. It's not how it's done in English.
I wouldn't rely on video games for correct use of English, by the way.